Terrorism and Beyond: Exploring the Fallout of the European Foreign Fighter Phenomenon in Syria and Iraq

by Jeanine de Roy van Zuijdewijn


The foreign fighter phenomenon in Syria and Iraq has led to many worries about the potential negative consequences that might occur in the near future. The scenario of returned foreign fighters launching attacks in the West is by far the most prominent one. This article aims to broaden the discussion on the potential fallout of the phenomenon by examining three particular dimensions: the physical threat (including the terrorist threat), ideological consequences, and societal consequences. After presenting these dimensions, three historical cases of jihadi foreign fighting (Afghanistan, Bosnia and Somalia) are examined to see to what extent different types of fallout materialized. The final part of the article attempts to gauge which indicators or signs of potential fallout are already observable in the case of the on-going conflict in Syria and Iraq. If we seek to prepare ourselves for the future fallout of today’s foreign fighter phenomenon, we must look beyond the terrorist threat.

Keywords: Foreign fighters; Syria,; Afghanistan;Bosnia; Islamic State; jihadi terrorism


The conflict in Syria and Iraq has attracted tens of thousands of foreign fighters [1] of which five to six thousand have come from Europe.[2] This has created serious concerns in European countries about the possible negative consequences, or fallout, of the foreign fighter phenomenon, particularly in the form of the potential terrorist threat posed by returning fighters. It is this scenario of returned foreign fighters staging attacks in Western countries that has featured most prominently in the majority of studies into the potential fallout of foreign fighting.[3] This specific angle that is mainly emphasized by counterterrorism professionals dominates the debate and overshadows other types of fallouts that we might have to face.

This article aims to contribute to a more comprehensive overview of the potential fallout of the foreign fighter phenomenon. It will do so by first exploring the often-mentioned physical threat in the form of terrorism and other types of violence that might be traced to foreign fighters. The focus will not be limited to short-term terrorist threats and violence in Western countries as longer-term consequences and those for the countries where these fighters go to will also be discussed. The second dimension that will be studied is ideology. Foreign fighting may lead to a growing appeal of, in this case, transnational jihadi ideology and bring with it an increased potential for recruitment by movements linked to that ideology. The third and final dimension that will be explored concerns the societal consequences of the foreign fighter phenomenon, such as polarization and securitization within the countries that the fighters depart from, reintegration in home countries as well as in post-conflict countries, and problems on a more personal level such as Post-Traumatic Stress Disorder (PTSD) and broken families.[4]

The aim is not to present a complete list of all forms of fallout but rather to broaden the current discussion by highlighting three particular aspects. The focus will be on jihadi foreign fighters, the dominant foreign fighter phenomenon of today, and the potential fallout of the conflict in Syria and Iraq. The first part of the article provides an overview of the three types of fallout (physical, ideological and societal). In the second part, these aspects of fallout are examined in three cases of jihadi foreign fighting: Afghanistan, Bosnia, and Somalia. It can be shown that certain types of fallout are prominent in some cases, but less so in others. The final part examines what fallout is to be expected from today’s presence of European foreign fighters in Syria and Iraq.

Types of Fallout

The Physical Threat

The first type of fallout is the violence and physical threat linked to foreign fighters. This includes the potential terrorist threat posed by returning foreign fighters who could come back further radicalized, battle-hardened, and subsequently use their experience and extremist links to launch new attacks.[5] This could happen during or after the conflict. Conversely, “wannabe” or failed foreign fighters who are unable to reach jihadi battlefields–regardless of whether they are stopped by the authorities or denied access by foreign fighter groups–might choose to engage in terrorism at home instead. Another scenario is that of sleeper cells that are instructed to stay under the radar for years before being reactivated to launch attacks. A final example linked to a terrorist threat in the home country originates from the presence of networks that are involved in recruitment and logistical support for groups in conflict zones. These networks might also broaden their activities and start focusing on home countries, effectively bridging the divide between foreign and domestic activities, such as has been studied extensively by Petter Nesser.[6] He has shown how jihadi plots in Europe “usually involve interaction between a cell and extremist networks in the attack country, as well as international networks”.[7]

Similarly, as there might be a nexus between domestic and foreign activities, there might also be a so-called “terrorism-crime”-nexus. This debated topic within terrorism studies has gained more attention in recent years.[8] Some scholars suggest that we should refrain from seeing terrorist organizations and “classical” criminal organizations as two contrasting types of either fully politically or non-politically motivated organizations.[9] Terrorist organizations often engage in criminal activities, such as robberies, drug trafficking or money-laundering to finance their operations. Besides the possible involvement of networks that support foreign fighters via criminal activities, foreign fighters might also use their experience to participate in other types of criminal activities upon return.

Another example of a physical threat is the impact foreign fighters could have on local conflicts.[10] An often suggested implication is that foreign fighters could broaden such conflicts by getting other parties that either support or fight them involved, or use their presence as an excuse to escalate a pre-existing conflict with local or regional adversaries. These fighters could also form new or strengthen existing terrorist organizations. Following insights from the field of negotiation studies, this could mean that conflict resolution could become more complicated, or that different negotiation strategies are required.[11] Many foreign fighters join the struggle of an insurgency against a state, vying for – in most cases – independence, change of government, or restoration of order. If foreign fighters join groups pursuing such causes and use terrorist tactics to that end, they might be called “conditional absolute terrorists who have something to negotiate about – territory, independence, conditions – even if their suicidal tactics are absolute”.[12] Another possible way in which foreign fighters could be linked to violence is by introducing more brutal tactics or different norms about what is allowed during combat, such as suicide attacks.

Another often-mentioned consequence for local conflicts is the impact foreign fighters might have on the strength and reputation of the side they are fighting for. It is often assumed that they strengthen the side they join in the battle. Kristin Bakke, however, has shown that it could also have the exact opposite effect.[13] This has been reconfirmed by more recent studies of Ben Rich and Dara Conduit, who have demonstrated that the presence of jihadi foreign fighters in Chechnya and Syria “have had a catastrophic impact on international and domestic perceptions of the opposition” and that “(i)n some cases, this has led observers to transfer support back to the antagonistic government, preferring the known government over the potentially destabilizing effects of a revolutionary jihadist regime”.[14]

In addition to the impact on the local conflict, foreign fighters could also be involved in violence outside the country itself. For instance, foreign fighters could continue to stay together after the conflict has terminated, and look for other places where they could continue their jihad. This idea of foreign fighters “hijacking local conflicts” has been mentioned in many studies.[15] The fighters could also leave the country to set up training camps somewhere else. The formation of al-Qaida and its activities in multiple countries around the world are a case in point. According to David Malet, the fact that foreign fighters do not return to their home countries does not mean the fighters did not desire to do so. He claims that this often resulted from “the policies of their home and host states that prevented reintegration and created cohorts of stateless, and now professionalized, actors who perpetuate in weakly-governed conflict zones.”[16]

The Impact on Ideological Currents and Recruitment

A second type of fallout relates to the influence the foreign fighter phenomenon could have on the reinforcement and spread of their ideology. In this case, this applies to the transnational jihadi ideology that emerged from the 1980s conflict in Afghanistan. Foreign fighters usually claim to fight in defense of a certain community that is facing an existential threat. A “transnational identity” links these fighters to the community they are fighting for.[17] This transnational identity is derived from adhering to a certain ideology and being part of movements linked to that ideology. This partly explains why Communists from close to fifty countries joined the International Brigades in Spain in the 1930s fighting alongside the Republican side against the Fascists under General Franco. Similarly, it explains why jihadis in the 1980s came to Afghanistan to support the local fighters against the “infidel” Communists. The experience of foreign fighting can profoundly influence the course of development of a particular ideology, the heroic stories that are being told about the accomplishments of those who adhere to the ideology, and the ideas of what it means to be part of such movements.

One specific example is the formation of a “foreign fighter legacy”. Regardless of their military accomplishments, foreign fighters tend to build a positive narrative, portraying themselves as a brave fighting force. This narrative or “political myth” connects the ideology to the idea of the fighters defending a certain transnational community. This type of narrative can have a long-lasting impact if future generations in these movements continue to see themselves as defenders of certain communities, and act accordingly. Mohammed Hafez, for instance, has shown how a specific “subculture of volunteerism and martyrdom” that was born in Afghanistan remained to be highly influential in many subsequent conflicts.[18] Another example of how foreign fighters’ experiences could have a long-lasting influence on ideology is the formation of an enemy image. Fighting in a battle and, equally important, being attacked by others determines who is perceived as the enemy.[19] As a consequence, even those who are not directly involved in fighting against these foreign fighters but who condemn it or try to stop them from joining – such as authorities blocking fighters to leave – might also be seen as hostile actors. This determines the position vis-à-vis other actors and also contributes to narratives of the groups.

Another important aspect of ideological fallout is the splitting of local insurgent groups and the radicalization, or further “extremization” of certain groups, or an ideological current. This aspect has been studied by Rich and Conduit who conclude – with regard to the cases of Chechnya and Syria – that this has led to “a jihadization of the opposition”.[20] The jihadi foreign fighters managed to normalize the portrayal of the struggle in Chechnya as a civilizational clash between Islam and the rest of the world. It also led to a split in the opposition between those who saw the struggle more as a secular and nationalist one and those who stressed the jihadi and religious nature of it.[21] Similarly, splits in movements could also occur around methods that are permitted in combat, and ideas about where the next battle should be waged. It could also revolve around the question whether it is mainly a local fight or that a global agenda should be pursued.

In addition to these possible consequences relating to ideology formation, it could also strengthen the reach of an ideology. For instance, the presence of foreign fighters often manages to draw international attention to the conflict and the proclaimed cause they are fighting for. Thus, it might be used as a successful tool to draw (renewed) attention to a cause, and can be part of propaganda efforts to frame the conflict in a certain way. It could also provide renewed legitimacy to a cause or ideology that appears to have lost importance. The presence of foreign fighters could prove that certain transnational identities are relevant and need to be defended, such as happened when Abdullah Azzam stressed the individual obligations linked to transnational jihadism (to be discussed below). Another example of how the reach or appeal of an ideology could be strengthened is related to the earlier-mentioned foreign fighter legacy. Returned foreign fighters could enjoy a kind of street credibility and status as experienced fighters. Their role model and presence in certain communities could motivate a next generation to become foreign fighters.[22]

The Impact on Societies

A third and final type of fallout encompasses the consequences for societies. The foreign fighter phenomenon could, for instance, affect national policies and perceptions on (counter-) terrorism and related issues, such as immigration. Polarization could arise when foreign fighters are part of a particular ethnic, religious, or ideological group in the home country. The general population could become anxious about alleged support for militancy – or lack of public condemnation of it – among affected diaspora communities. Additionally, returning fighters will commonly be seen as a potential threat, resulting in public calls for fierce and immediate actions to counter this threat. Conversely, anxiety can stem from measures taken by authorities targeting these specific ethnic, religious or ideological groups. Furthermore, securitization could occur, which means that the issue of foreign fighters is increasingly perceived to be an important security threat, and that specific measures or resources need be mobilized to address it.[23] It could lead to higher levels of fear among the general population, or result in other (security) issues moving down the ladder of policy priorities, as resources and attention are devoted to this particular issue.[24]

Another example of societal consequences for the home countries is the reintegration process of returned fighters. Depending on the actions that have been linked to foreign fighters in the conflict zone (e.g. war crimes, beheadings, torture and rape), and the general stance of the authorities towards the foreign fighter phenomenon, returning fighters might be closely monitored, prosecuted, detained, or become part of intensive rehabilitation programs. This could result in a serious strain on the resources of various agencies, ranging from the public prosecution service, the prison system, the intelligence services to social workers or probation services involved in accompanying their return into society. The same applies to efforts to try to prohibit young Muslims from becoming foreign fighters.

Some of the societal consequences for the (post-)conflict country might be related to physical threats. For instance, disturbed relations between sectors of society could lead to violent clashes. In discussions about the (social) peace in a post-conflict country, these issues are often subsumed under the acronym “DDR” – disarmament, demobilization and reintegration. These are generally regarded to be key components of post-conflict peace consolidation, with re-integration being more society-oriented and disarmament and demobilization being more security-oriented.[25] Problems might arise when, for instance, foreign fighters choose to stay in the post-conflict country and refuse to disarm. They might ignore requests by the post-conflict authorities to leave the country. In other cases, they are invited to stay and receive citizenship as a reward for their fighting efforts. The presence of these armed individuals and groups could lead to tensions, and become an obstacle towards a more peaceful future. When they disarm, there might still be barriers to full integration in the country, as they often adhere to different norms and habits. This could result in a strenuous and potentially volatile relationship with the local population. Pressure could also be put on the post-conflict authorities to prosecute or extradite these fighters if they are suspected of having been involved in war crimes or acts of terrorism. Unwillingness or inability to do so could damage the international reputation of the post-conflict country, and might result in these countries being labelled as “state sponsors of terrorism” and thereby become subject to sanctions.[26]

At the individual, personal level, there are multiple forms of fallout. Most of these are predominantly relevant for the fighter himself, but some also have a clear impact on society. Two important examples are the consequences of Post-Traumatic Stress Disorder (PTSD), and the issue of broken families. Several studies have established a link between combat experience and a lack of training to cope with traumatic events on the one hand, and the risk of PTSD on the other.[27] It is also known that PTSD has serious ramifications for the quality of life of those affected, and might result in behavior that could endanger those suffering from PTSD as well as those in their immediate social surroundings. Combat exposure is linked to increased risks of abuse of a spouse, depression, and substance abuse.[28] Foreign fighters could thus introduce these kinds of problems into society upon their return. Then there is the impact on families. Foreign fighters frequently leave behind broken families in the home country who are in most cases confronted with the loss of a husband or son. This could affect the life of the family members, most obviously on the emotional level but also economically. These challenges might be further exacerbated when families are stigmatized or feel deeply hurt or ashamed because a family member has left to become a foreign fighter.[29]

Fallout from Historical Cases of Foreign Fighting

An examination of historical cases of foreign fighting illustrates how certain types of fallout might be present in some cases while being less relevant in others. Each case of foreign fighting has its own characteristics and dynamics that will determine whether or not certain forms of fallout can be identified. The following takes a brief look at the consequences of jihadi foreign fighting in three particular cases Afghanistan (1980s), Bosnia (1990s), and Somalia (2000s). These cases have been discussed in more detail elsewhere and are here used to concretize and illustrate the types of fallout that were discussed in more general terms earlier.[30] Admittedly, an examination of other cases of jihadi foreign fighting could lead to other results. The selection of these three cases is motivated by a desire to study the fallout of foreign fighting in different regions (South Asia, Europe, Africa) and different contexts (pre- and post-9/11).

The Physical Threat

Examples of physical fallout can be seen in all three cases. It has been widely reported that foreign fighters who joined al-Shabaab in Somalia during the war against Ethiopia (2006-2009) introduced new methods of fighting such as suicide attacks.[31] One such attack was perpetrated by Abdulrahman Ahmed Haji, a Dane of Somali descent. Haji blew himself up during a college graduation ceremony and killed more than 20 people, including three government ministers.[32]

In terms of exacerbating the conflict and rising tensions between the local population and foreign fighters, we have seen clear examples in Bosnia and Afghanistan. For instance, the Bosnian army tried to put an end to the ruthless behavior of foreign fighters who were involved in horrendous atrocities and who regarded the local Bosnians to be impious Muslims. A deputy of the Bosnian army told the Western press that “[i]t was a mistake to let [the foreign fighters] in here (…). They commit most of the atrocities and work against the interests of the Muslim people”.[33] In Afghanistan, the foreign fighters were regarded with much suspicion as well. Not only did many lack fighting experience and dedication, there were also “ideological and cultural frictions” between the foreign fighters and the local fighters.[34] Al-Shabaab offers another interesting example as it appears that some foreign fighters turned into targets for some local fighters. Since 2010, many who were deemed too critical of the leadership or too outspoken about internal affairs have been killed or prohibited from leaving the group.[35]

The scenario of experienced foreign fighters travelling to other conflict zones was most visible in Bosnia, where several Afghan veterans had joined the fight. After the Soviet Union had withdrawn its troops from Afghanistan in 1989, in-fighting intensified between the different groups. The fall of the Najibullah regime in 1992 and the outbreak of the civil war made the idea of a defensive jihad, as had been propagated by Abdullah Azzam, redundant. The war in Bosnia proved to be an opportunity for a number of Afghan veterans – unwilling or unable to return home – to fight there. Furthermore, groups like al-Qaida recognized that Bosnia might offer an opportunity to set up training camps or eventually stage attacks against other enemies.[36] However, despite the hopes of some jihadi groups to use Bosnia as a “springboard” for terrorist activity elsewhere, this never materialized. The impact of such conflicts on the mobilization and radicalization processes of many jihadis in Europe was large, but rather reflects the ideological impact as will be discussed in the next section. The three cases provide examples of how the focal point of militancy can move from one jihadi theatre to another. The aftermath of the war in Afghanistan demonstrates how foreign fighters could continue their activities in other countries. This could be by way of direct engagement in other conflicts as well as take the form of a consolidation of a transnational terrorist network such as the one of al-Qaida, that subsequently planned terrorist attacks in multiple countries.

Concerning the terrorist threat, we see some examples of returned foreign fighters who became involved in terrorism in their home country. One example is the so-called “Roubaix Gang”, of which two members, Christophe Caze and Lionel Dumont, had fought in Bosnia. They planned to detonate a car bomb during a G7-meeting in Lille, but the police disarmed the bomb and arrested the members.[37] Another foiled plot was linked to British-Jamaican fighter Andrew Rowe, who had not only fought in Bosnia, but allegedly also met with Islamists in other parts of the world. Rowe was arrested in 2003 on the French side of the Channel tunnel with traces of high explosives in his socks.[38] None of those European Bosnia returnees actually managed to stage a successful attack.

Another important insight is provided by studying the link between foreign fighting and radical activity – such as fundraising, propaganda, and recruitment for terrorism–in the home country. The clearest example is perhaps London where many foreign fighters found an environment in which they could focus on a variety of activities: giving radical sermons but also making connections between cells abroad and at home to help potential foreign fighters reaching conflict zones.[39] A study by Petter Nesser found similar scenarios emerging in several other European countries in the 1990s.[40]

The most well-known example of a threat posed by a foreign fighter, although not a returning one but someone who remained abroad, is Osama bin Laden, who plotted attacks in a foreign country against multiple other countries. Two of the 9/11 hijackers presumably also fought in Bosnia.[41] Other important examples are the attacks perpetrated by al-Shabaab in neighboring countries such as Kenya, Uganda and Ethiopia, although the direct involvement of foreign fighters remains unclear. Another case is offered by Michael Adelobajo. This British citizen apparently tried to join al-Shabaab in 2010 but was arrested by the Ethiopian authorities at the Somali border and was sent back to the UK. Three years later he killed the British soldier Lee Rigby on the streets of Woolwich, London.[42] This example shows how failed foreign fighters could equally pose a security threat.

Impact on Ideological Currents and Mobilization

The importance of the three episodes of foreign fighter experiences in terms of ideological fallout cannot be overestimated, particularly in the case of Afghanistan. Although the foreign fighters mostly played a marginal role during combat, their presence in the conflict zone contributed to the idea of a foreign fighter legacy that still resonates today. According to Petter Nesser, “it was the Arab volunteers in the anti-Soviet struggle who created the ideologies and movements that would become referred to as “jihadism”.[43] A key figure in the mobilization for the fight in Afghanistan was the Palestinian sheikh Abdullah Azzam. Thomas Hegghammer has described how Azzam “is still an icon of the Islamist movement, and among radicals his stature is only matched by Osama bin Laden’s”.[44] He managed to draw tens of thousands of fighters to the area. Perhaps more importantly, he took “the first step toward a more global vision of jihad”, although he himself never focused on targeting the far enemy by way of terrorist attacks on foreign soil.[45] The case of Afghanistan also shows how internal disagreements arose. Stéphane Lacroix showed that the foreign fighter movement in Afghanistan became increasingly split into several camps. Fierce competition arose between, for instance, al-Zawahiri and Abdullah Azzam about the young Bin Laden.[46] Another point of contention between the two was which enemy should be targeted: the external enemy (according to Azzam) or the apostate Muslim regimes (according to al-Zawahiri).[47] Fawaz A. Gerges even goes so far as saying that “it is doubtful that transnational jihad would have materialized without the prolonged Afghan war and its socializing and mobilizational effects”.[48]

The conflicts in Bosnia and Somalia provided pretexts for the invocation of a defensive jihad. This was particularly relevant in the case of Bosnia. The conflict started shortly after Afghanistan had seemed to have lost much of its original appeal. Similarly, the Ethiopian invasion in Somalia in 2006 was framed as another instance of the “crusaders” attacking the Islamic world. Al-Qaida deputy leader Al-Zawahiri stated it as follows: “My Muslim brothers everywhere (...) While I am addressing you today, the crusader invading Ethiopian forces are violating the Islamic land of dear Somalia. (…) Here, I am urging the Islamic nation in Somalia to be steadfast in this new crusader battlefield, which America, its allies, and the United Nations are waging against Islam and Muslims”.[49] A few years later, Bin Laden issued a video titled “Fight On, Champions of Somalia”.[50] Conflicts like those in Somalia and Bosnia demonstrated to potential supporters what it would mean to be a jihadi and who should be seen as enemies of Islam.

The presence of foreign fighters in these conflicts also managed to draw international attention to the cause. The foreign fighters were often aware of the opportunity to frame the conflict in a favorable way. During the Bosnian conflict, videotapes were distributed in numerous, mainly Arab, countries, showing mutilated corpses and wounded civilians. They added “footage from World War II concentration camps to draw parallels between the past slaughter of Jews and the current slaughter of Muslims by European Christians”.[51] In Bosnia, the frame was that the West was doing nothing to stop innocent civilians from being slaughtered. The jihadis were the only ones coming to help. As reported by Raffaello Pantucci, Lorenzo Vidino and Evan Kohlmann in their study of al-Shabaab, these kinds of conflicts ensured that “the global jihadist movement also benefits, as it can expand its influence and add credibility to its narrative that Islam is under attack from non-Muslims”.[52] Still, some critical remarks about the “ideological success” of these conflicts need to be made. Thomas Hegghammer, for instance, has shown how the Bosnian jihad was an “anti-climax” for the Saudi jihadi movement “because it never took the proportions of the Afghan jihad and because the Arabs were not welcome in Bosnia”.[53]

Another form of ideological fallout was the role played by returned foreign fighters in recruiting others to become foreign fighters. In particular, the Arab veterans from Afghanistan gained such a reputation. For instance, Abu Hamza al-Masri, became one of the key figures of the Finsbury Mosque in London in the late 1990s. He had also been in Bosnia, and this experience made him a persuasive recruiter. Another example is Anwar Shaaban, a senior leader of Al-Gama’at al-Islamiyya who had fought in Afghanistan and had contacts with Sheikh Omar Abdul Rahman and Al-Zawahiri. After obtaining asylum in Italy, he was the central node in recruiting Europeans to fight in Bosnia.[54]

The Impact on Societies

The three cases show mixed societal consequences. For instance, there is a difference in the levels of polarization that seemed to occur in the home countries. Generally speaking, the relatively low numbers of foreign fighters meant that the discussion in the home countries never became quite intense, and that reintegration problems of returning foreign fighters seemed to have remained manageable. It was not only numbers, but also the public and official stance towards the foreign fighter phenomenon that mattered. For instance, during the war in Afghanistan, the fighters could sometimes count on the sympathy of the population in the home country. The American jihadis in Afghanistan were fighting the Cold War enemy of the US. As reported by J.M. Berger, this meant that those who went there could still be seen as “good Americans”.[55] It is important to stress that these three conflicts took place in very different international contexts. During the war in Bosnia, al-Qaida had not yet launched terrorist attacks against the West. The attacks on 9/11 drastically changed the attitude of Western countries towards foreign conflicts with jihadi elements. Similarly, it also resulted in a different attitude towards the people who aimed to take part in these fights. Thus, the post-9/11 context of Somalia and the prominence of the jihadi threat on many security agendas in Western countries make this case very different from Afghanistan and Bosnia.

The situation with regard to Bosnia shows similarities with the case of Afghanistan. The numbers of foreign fighters were too low to lead to much upheaval in the (at least Western) countries where the fighters departed from. Also, it has been said that the presence of foreign fighters was “tacitly consented to both by Bosnians and by the international community”, similar to what happened in Afghanistan.[56] Here again, the sympathetic media reporting regarding the conflict “opened up the pool of recruits to a much wider range”.[57] However, the departure of foreign fighters from Western countries did at times lead to suspicion and investigations. This was particularly relevant in a number of key recruitment centers, such as in Milan. In 1995, during operation “Sphinx” of the Italian intelligence agency, seventeen militants were arrested at the Intercultural Institute (ICI) while many more were subject to investigation.[58] Interestingly, wider pressure on the authorities to close the institute did not materialize when its links to the Bosnian jihad became apparent. This only happened after the attacks on 9/11 when it became clear that the ICI seemed to be “one of Al Qaeda’s main recruiting stations” in Europe.[59]

Instead of polarization or securitization within the countries where the foreign fighters left from, the Bosnian case shows how this could occur within the post-conflict country itself. This is linked to the issue of reintegration of fighters. After the 1995 Dayton Agreement, foreign forces were officially ordered to leave the country within thirty days. The foreign fighters, however, were in many cases granted citizenship as a reward for their fighting efforts. This allowed them to stay, and it has been estimated that at least 700 to 1000–but some sources report up to 3,000 militants [60]–of them have stayed. They mostly formed their own enclaves in former Serb towns surrounding Maglaj, reportedly with sharia law in place.[61] However, it was also said that many of the fighters married widowed Bosnians and lived “undisturbed with their new families in other people’s [former Serb] houses”.[62] After 2000, when some Serbs reclaimed their original houses, the Bosnian government evicted the former fighters from these villages. Whereas there was perhaps only limited integration of these fighters into the new Bosnian state, real violent incidents seemed to have been rare. However, tensions between the Bosnian Muslim population and the often much more conservative foreign fighters incidentally rose. Some report that there was a “cultural and religious uneasiness” between the two.[63] That uneasiness slowly transformed into something more pressing, namely a general fear that the “potentially threatening forms of Islam that the Mujahideen had brought with them to Bosnia were spreading, and that any potential ties the former Mujahideen may have to al-Qaida were threatening to turn the country into a sanctuary for terrorists and terrorist training”.[64]

This shows how the presence of foreign fighters was initially accepted as a simple fact of post-conflict Bosnia, but was later securitized by the Bosnian government and international actors, especially after the attacks on 9/11. These attacks formed a major turning point in the Bosnian authorities’ stance towards the former fighters, as they decided to withdraw the citizenship of many of them. A proven link to 9/11 or terrorist activity is still disputed.[65] As reported by Jennifer Mustapha, their mere past as former jihadi fighters was enough to invoke this idea of a threat.[66] According to Stephanie Zosak, ‘[t]his scrutiny of the mujahideen is a direct response to pressure the international community has put on the Bosnian government to take action against these individuals due to concerns that they may use Bosnia and Herzegovina as a base for promoting and perpetrating acts of terrorism”.[67] However, other sources suggest that it might be oversimplified to claim that the perception of the former foreign fighters as a threat was only motivated by some kind of political agenda. It has been said that the Bosnian State Intelligence Agency (OSA) had been genuinely worried about the lack of integration of some of these former fighters and the consolidation of Islamist networks in parts of the country.[68]

In the case of Somalia, the situation is different. Most foreign fighters joined al-Shabaab that is on the lists of designated terrorist organizations of, amongst others, the US and UK.[69] Michael Taarnby and Lars Hallundbaek point to the UK and the Scandinavian countries as places where recruitment for al-Shabaab has been particularly problematic.[70] In their attempts to interview members of the Somali Diaspora community in Denmark about their views on the terrorist organization, the authors were confronted with a lot of hesitation to cooperate. Many in the Somali Diaspora find this topic extremely sensitive to talk about, and are sometimes threatened by those with sympathies for al-Shabaab if they speak out.[71] Many European countries regard foreign fighters who have joined the conflict in Somalia to be a potential threat, as can for instance be seen in a 2010 statement by the British head of MI5, who said that Somalia had become one of the most serious bases for potential attacks against the UK.[72] This means the Somali diaspora communities are experiencing pressure from several sides: from within – where talking about al-Shabaab to outsiders is not allowed – but also from outside, as the debate about Somali youth leaving to fight is sometimes tied to debates about immigration and integration of minorities. There is, however, another side to polarization that seems to have been more prominent in these cases: stigmatization within Somali diaspora communities. In a US Congressional Hearing, a Somali community leader and uncle of a foreign fighter called Osman Ahmed voiced his frustration and difficulties with sharing information with the authorities. Ahmed stated that:

“… we have been painted as bad people within the Somali community by the mosque management. We have been threatened for just speaking out. Some members of Abu-Bakr Al-Saddique mosque told us that if we talk about the issue, the Muslim center will be destroyed and Islamic communities will be wiped out. They tell parents that if they report their missing kid to the FBI that FBI will send the parents to Guantanamo Jail. And this message has been very effective tool to silence parents and the community”.[73]

This statement illustrates how members are stigmatized within their own community and how they are afraid to speak out. Ahmed also testified how entire families are affected by the decision of a child to travel to Somalia. Not only do these families have to cope with their own anger and sadness, the stigmatization makes them unwanted elements within their own environment.

Reports about the impact foreign fighting could have on the former fighter himself are usually anecdotal in nature. The cases or stories that managed to attract attention are often tied to some broader political discussion. One such case is Imad al-Husein, a Syrian national who fought along the foreign fighters in Bosnia, received citizenship, married a Bosnian widow and continued to live in the country.[74] Following the attacks on 9/11, however, al-Husein lost his citizenship, and in 2008, he was planned to be deported to Syria.[75] Al-Husein won an EHCR court case that prevented his deportation. The result was some kind of “legal limbo” that forced him to live in a deportation center for years.[76] His case attracted a lot of attention and rallies were organized to block his deportation, which – according to a leaked cable of the US Embassy in Sarajevo – was the result of a “skillful public relations campaign (…) [to] highlight (…) his role in the war in order to appeal to Bosniak public opinion.” At the same time the case also “has the potential to be appropriated by Bosnian Serbs for nationalist purposes as demonstrated by the sensationalist coverage of the Zenica rally in the RS press”.[77] This shows how such cases could be exploited by multiple actors.

The issue of PTSD rarely surfaces in reports about foreign fighters. There is little reason to assume this means it has not been an issue for some of these fighters. Several studies have linked combat experience as a risk factor to PTSD.[78] For instance, it has been estimated that between 13 and 20% of the American soldiers who have fought in Operation Enduring Freedom and Operation Iraqi Freedom might be suffering from PTSD.[79] There is reason to believe this number might be equal, if not much higher among former foreign fighters as some of the “mitigating factors” that are often present in official armies – good training and proper aftercare – seem to be absent.

Potential Fallout of Jihadi Foreign Fighting in Syria and Iraq

Before summarizing the extent to which the three types of fallout have been observed in these three cases, one final question will be addressed. Against the backdrop of today’s large presence of foreign fighters in Syria and Iraq, the question arises if we can expect similar types of fallout as shown in the case studies. This is a difficult question as the conflict is still on-going and the eventual fallout will be influenced by many factors that cannot be foreseen at this moment. Despite these obvious limitations, this section will examine what we already see and discuss what to expect.

One difference between the foreign fighter phenomenon in Syria and Iraq today and the historical cases relates to the magnitude. Around 5-6,000 European foreign fighters have joined the conflict on the side of jihadi groups.[80] Against this backdrop, the magnitude of the fallout can be expected to increase as well. The reality of foreign fighters joining a terrorist organization with a transnational agenda is not a new phenomenon. As shown in the historical cases, terrorist organizations were present in two of these conflicts – Bosnia and Somalia – and were the product of the third one – Afghanistan. In all of the foreign fighter movements, there have been elements with a more global than a local agenda, and most of these groups did not shy away from using terrorist tactics.

The most visible fallout of the conflict in Iraq and Syria today is the physical threat. For instance, we have seen multiple examples of plots and attacks by returnees or sympathizers in European countries (Brussels: 2014, 2016; Paris: 2015).[81] Foreign fighters who are still in Syria or Iraq have also been involved in planning some of these attacks. Most analysts predict that organizations such as Islamic State will continue to try to launch attacks abroad, with Europe as one of its main targets.[82] This strong terrorist element makes the current conflict fundamentally different from the historical cases of foreign fighters that were discussed, and it is therefore not just an example of a particularly large foreign fighter mobilization. This analysis seems plausible as IS has been very vocal about its desire to launch terrorist attacks outside the conflict zone. In addition to that, IS’ spokesman al-Adnani – again – urged followers of IS in a speech in May 2016 to launch attacks independently if they are unable to reach areas of IS control.[83] His call appeared to be related to the military losses the organization has been facing lately and the fact that the numbers of new fighters joining IS has been declining, forcing IS to “stimulate” attacks in addition to organizing these themselves.[84]

Another crucial difference with the three historical cases is that IS has announced the establishment of a “Caliphate” in parts of Syria and Iraq, and could be called a quasi- or proto-state, although it is currently facing increasing pressure and losing territory. The Caliphate narrative has strongly affected and even partially changed the ideological appeal of joining the conflict.[85] It does not only attract those who wish to fight to liberate Muslim lands from foreign “occupation”, but also those whose main aim is to live in what is said to be a true Islamic state. The organization tries to convince fighters that they can join something “new” in the Caliphate, and that this is the “simplicity and unity that they imagine existed in the earliest days of Islam”.[86]

Great uncertainty surrounds what will happen in the “post-conflict country” straddling Syria and Iraq. Analyzing the battle near Mosul that started in October 2016, the Soufan Group noted that “deep internal sectarian and ethnic divisions will play a significant role in the long-term outcome in Mosul”.[87] The position of foreign fighters will be just one of the myriad challenges that Syria and Iraq will have to face. If the Islamic State were to be militarily overrun, the question is what will happen to the foreign fighters who are still alive. Much will depend on whether foreign fighters will be able to stay in these countries as well as the policies that are implemented in their home countries. They might remain in Syria and Iraq when the face prosecution in their home countries. Some might choose to move to countries where they think they can escape prosecution.

Foreign fighters might also move to another conflict zone, either in response to policies in the “post-conflict countries”, or motivated by a desire to continue fighting a jihad elsewhere. This will have regional implications. For instance, it has already been observed that foreign fighters are increasingly moving to the “next” battle zones, including Libya.[88] This movement of battle-hardened jihadis from one conflict zone to the next one would very much align with the insights from historical cases, where those who most strongly believed in the transnational duty of conducting a jihad did not choose to return home but continued to fight elsewhere. Given the current developments and changes on the ground, it is too early to conclude on what might happen.

Another question relates to the potential ideological fallout. The historical cases have shown that the actual numbers of fighters or their military accomplishments are not the most important factors when it comes to ideological impact. All three cases demonstrated how the experience of foreign fighting contributes to a foreign fighter legacy that can affect the strength and expansion of an ideology. The case of Afghanistan is the clearest example, which is partially a result of the duration of the conflict and the number of fighters involved, but also because of the importance of individuals like Azzam, al-Zawahiri and Bin Laden. Both Afghanistan and Somalia showed signs of the extremization of an ideology, while the case of Somalia showed how foreign fighters themselves could become victims of power struggles and ideological debates, something which might have occurred in all three cases. The case of Syria and Iraq already reveals similar signs of the extremization of movements, and partially as a result of that, splits within movements. The current battle between IS and Jabhat Fateh al-Sham (formerly Jabhat al-Nusra – JaN) is an example. Aaron Zelin analyzed the struggle between the two groups in 2014, and noted that whereas al-Qaida’s leadership was worried about excessive violence and losing support of local communities, the use of extreme methods and their potential blowbacks appear to be less of an issue for those who joined IS.[89] Several foreign fighters left JaN to join IS when the latter rose to power in parts of Syria. As with the historical cases, we can expect that the conflict in Syria and Iraq will remain influential on jihadi ideology in the decades to come. Despite the fact that IS might be militarily defeated and that other groups might take over, the experience of having managed to establish a self-proclaimed Caliphate with the help of foreign fighters, can be expected to feature prominently in future jihadi propaganda and might again attract future fighters.

Where the current case seems to deviate most strongly from the historical cases presented earlier is the societal fallout. The “foreign fighter phenomenon” has become the number one security issue in many countries. Many resources and much attention are now devoted to this issue. This was clearly not the case in most of the historical cases of foreign fighters, where it was often condoned in their countries of origin and not regarded to be an important security issue. Today the foreign fighter issue has become strongly securitized and criminalized, and has increased levels of fear of terrorism in European countries.[90] Other indicators of the potential societal fallout are polarization and distrust. Reciprocal radicalization between jihadis and other Islamists on the one hand and anti-Islam movements on the other hand is one aspect of this. Polarization and tensions between communities are for instance visible in the actions of right-wing popular movements such as Pegida – the Patriotic Europeans Against the Islamisation of the West. One well-known Pegida-sympathizer, Felix Menzel, for instance stated in one of the first interviews after the organization was founded in late 2014 that he believed that what is unfolding in Iraq and Syria at the moment is a clear harbinger of the first global civil war”.[91] Organizations like Pegida show how the issue of foreign fighters and broader discussions about (Islamic) radicalization are often tied to other societal issues such as immigration.

Another example of this increasing distrust and polarization is the pressure put on Muslim communities to speak out against IS and terrorism. In a study of the German Institute for International and Security Affairs, it is stated that “these demands reinforce negative associations of Islam with terrorism and violence, and nourish threat perceptions and anti-Islamic prejudices, which in turn contribute to Muslims feeling increasingly excluded in Europe. Extremists can take advantage of this alienation for recruiting purposes”. [92] While this statement is not limited to the foreign fighter phenomenon but holds for jihadism in general, the issue of large numbers of Muslim citizens leaving to fight for jihadi causes has brought the issue much closer to home in many parts of the world.


This article approached the potential fallout of today’s jihadi foreign fighter phenomenon by not only looking at the potential terrorist threat posed to Western countries but by also discussing its ideological and societal dimensions. After examples of these types of fallout were provided, three historical cases of jihadi foreign fighting were examined. These three cases showed a somewhat mixed picture. With regard to the physical threat, all three cases indicated that this was clearly present. The scenario of returning foreign fighters launching attacks does not appear to have featured very prominently in these three historical cases. However, examples were found of foreign fighters who remained abroad and launched attacks, or who moved to a next conflict zone, especially in the case of Afghanistan. In addition, the three cases demonstrated that the presence of foreign fighters often led to conflictual relations with local militants, and that they were not always welcome. The case of Somalia provided an example of how a foreign fighter who was prevented from travelling to the conflict zone eventually became implicated in terrorist activity in the home country.

Regarding the ideological fallout, all three cases contributed to the strengthening of a foreign fighter legacy, although more so in the case of Afghanistan, than Bosnia and Somalia. The idea of fighting a “defensive jihad” to protect a transnational Muslim community still resonates today. In addition, spokesmen of foreign fighters managed to frame the conflict and their enemies in ways that boosted ideological impact. Returning fighters also played key roles in recruitment and managed to transform their real or alleged battlefield accomplishments into heroic stories about their jihadi experiences. Their street-credibility and status as returned foreign fighters should not be underestimated.

When it comes to societal fallout, polarization and securitization in European home countries appeared to have been a relatively minor issue historically, although the case of Somalia deviated from this. Whereas foreign fighters in Bosnia and Afghanistan could mostly count on support or passive tolerance within their home countries, this was not the case with regard to Somalia. In this post-9/11 context, foreign fighters joined an organization that was listed by many countries as a terrorist organization. The Somali case also showed how families of foreign fighters might become affected in the home country. Societal fallout in the post-conflict country was most visible in the case of Bosnia, where foreign fighters were initially welcomed but later became unwanted elements. This was partially the result of securitization processes following the attacks on 9/11 when new views on jihadism and international pressure resulted in changed attitudes towards former foreign fighters, who were increasingly viewed as a potential threat. However, it was also partially the result of reintegration problems and tensions between the former foreign fighters and the local population in Bosnia itself.

These three cases illustrate how the fallout of the foreign fighter phenomenon encompasses more than the possible terrorist threat posed to Western countries by returning foreign fighters. In the case of Syria and Iraq, we have already seen that this latter threat is real. However, the threat for the region itself, as well as the potential fallout related to the ideology and especially the societal dimensions need to be acknowledged. There are indications of a potentially substantial ideological and societal fallout from the wars currently raging in the Middle East. Whereas authorities are already devoting much of their attention to curbing the (potential) terrorist threat, it is as important to pay closer attention to the challenges that are linked to the other two dimensions.

About the Author: Jeanine de Roy van Zuijdewijn is a Ph.D. Candidate at the Institute of Security and Global Affairs of Leiden University, Research Fellow at the International Centre for Counter-Terrorism and Country-Coordinator for the Dutch-Flemish network of Ph.D.-theses writers of the Terrorism Research Initiative (TRI). Jeanine is grateful to the reviewers and Prof. dr. Edwin Bakker for their helpful feedback on earlier drafts of this article. Any errors are the responsibility of the author.


[1] The article will follow Malet’s definition of foreign fighting–“non-citizens of conflict states who join insurgencies during civil conflict”, see David Malet, Foreign Fighters: Transnational Identity in Civil Conflicts. New York: Oxford University Press, 2013, p.9.

[2] The latest estimates are that more than 30,000 foreign fighters have joined jihadi groups, see for instance The Soufan Group, “Foreign Fighters: An Updated Assessment of the Flow of Foreign Fighters into Syria and Iraq,” 2015, p.4.

[3] This observation has also been made by Ben Rich and Dara Conduit. In an earlier article in Perspectives on Terrorism, the author of this article has applied the same focus. See Jeanine de Roy van Zuijdewijn, “The Foreign Fighters’ Threat: What History Can(not) Tell Us” 8, no. 5 (2014): pp. 59–73. Thomas Hegghammer studied why jihadis choose to go abroad or stay at home, and the terrorist threat posed by returnees in: Thomas Hegghammer, “Should I Stay or Should I Go? Explaining Variation in Western Jihadists’ Choice between Domestic and Foreign Fighting”, American Political Science Review 107.01 (2013): pp.1-15. Daniel Byman studied the terrorist threat to Western countries as well as to the Arab world; see Daniel Byman, “The Homecomings: What Happens When Arab Foreign Fighters in Iraq and Syria Return?,” Studies in Conflict & Terrorism 0731, no. May 2015 (2015): pp.1–22. Other examples are: Brian Michael Jenkins, “When Jihadis Come Marching Home,” Rand Corporation, 2014; Jytte Klausen, “They’re Coming: Measuring the Threat from Returning Jihadists,” Foreign Affairs, 2014; Thomas Hegghammer and Petter Nesser, “Assessing the Islamic State’s Commitment to Attacking the West,” Perspectives on Terrorism 9, no. 4 (2015): pp.14–30; Andrea Barzon and Orsola Greco, “Fighting Abroad: The Foreign Fighters Phenomenon in the Scope of International Law, the ‘Blowback Effect’ and National Counter-Terrorism Measures,”, 2015, available at Available at SSRN, URL:, 2015.

[4] These three dimensions do not encompass all forms of spin-off effects. A different categorization of fallout – such as short-term vs. long-term consequences, or consequences for the conflict country vs. the home country – would have been possible as well.

[5] See for instance the Dutch threat assessment, National Coordinator for Counterterrorism and Security, “DTN 32,”, March 13, 2013. URL:

[6] Petter Nesser, Islamist Terrorism in Europe. A History. London: Hurst & Company, 2015, p.8.

[7] Ibid.

[8] See, for instance, Steven Hutchinson and Pat O’Malley, “A Crime–Terror Nexus? Thinking on Some of the Links between Terrorism and Criminality,” Studies in Conflict & Terrorism 30, no. 12 (2007): pp.1095–1107. See also Basra & Neumann’s contribution in this Special Issue.

[9] Tamara Makarenko, “The Crime-Terror Continuum: Tracing the Interplay between Transnational Organised Crime and Terrorism,” Global Crime 6, no. 1 (2004), pp.129–45.

[10] In a 2014 International Security article, Kristin Bakke has outlined the various ways in which this is possible; see Kristin Bakke, “Help Wanted? The Mixed Record of Foreign Fighters in Domestic Insurgencies,” International Security 38, no. 4 (2014): pp.150–87.

[11] Scholars like William Zartman have analyzed how the type of organization influences the chances of success at the negotiation table. Certain types of organizations, the “revolutionary absolute”, will never compromise, because violence is an end in itself; see I. William Zartman, “Negotiating with Terrorists,” International Negotiation 8, no. 3 (2003), p.446.

[12] Ibid.

[13] K. Bakke, “Help Wanted? The Mixed Record of Foreign Fighters in Domestic Insurgencies,”, p.185.

[14] Ben Rich and Dara Conduit, “The Impact of Jihadist Foreign Fighters on Indigenous Secular-Nationalist Causes: Contrasting Chechnya and Syria,” Studies in Conflict & Terrorism 38, no. 2 (2014), p.125.

[15] See for instance, Lorenzo Vidino, Raffaello Pantucci, and Evan Kohlmann, “Bringing Global Jihad to the Horn of Africa: Al Shabaab, Western Fighters, and the Sacralization of the Somali Conflict,” African Security 3, no. 4 (2010), pp.216–238; Marc Sageman, Understanding Terror Networks. Philadelphia: University of Pennsylvania Press, 2004, p. 58; Babak Rezvani, “Reflections on the Chechen Conflict: Geopolitics, Timing and Transformations,” Middle Eastern Studies 50, no. May 2015 (2014), p.8.

[16] David Malet, “Foreign Fighter Mobilization and Persistence in a Global Context,” Terrorism and Political Violence 2, no. 3 (2015), p.1.

[17] D. Malet, Foreign Fighters: Transnational Identity in Civil Conflicts, p.4.

[18] Mohammed H. Hafez, “Martyrs Without Borders: The Puzzle of Transnational Suicide Bombers,” in Marie Breen-Smyth (Ed.)The Ashgate Research Companion to Political Violence, New York: Ashgate Publishing, 2012, p.186.

[19] For a theoretical view on how enemy images are being formed, see for instance Louis Oppenheimer, “The Development of Enemy Images: A Theoretical Contribution,” Peace and Conflict: Journal of Peace Psychology 12, no. 3 (2006), pp.269–92; William Eckhardt, “Making and Breaking Enemy Images,” Bulletin of Peace Proposals 22, no. 1 (1991), pp.87–95.”

[20] B. Rich and D. Conduit, “The Impact of Jihadist Foreign Fighters on Indigenous Secular-Nationalist Causes: Contrasting Chechnya and Syria,”, op. cit., p.125.

[21] Idem, p.116.

[22] See for instance Petter Nesser’s discussion about “Londonistan”, in his volume Islamist Terrorism in Europe, London: Hurst, 2015, p.37.

[23] See Barry Buzan, Ole Waever, and Jaap de Wilde, Security: A New Framework for Analysis. Covent Garden: Lynne Rienner Publishers, 1998.

[24] Edwin Bakker and Jeanine de Roy van Zuijdewijn, “Jihadist Foreign Fighter Phenomenon in Western Europe : A Low-Probability, High-Impact Threat,” The Hague, ICCT, 2015.URL:

[25] For a discussion about successful “DDR” – Disarmament, Demobilization and Reintegration – and the role played by factors on a micro level, see M. Humphreys and J. M. Weinstein, Demobilization and Reintegration, Journal of Conflict Resolution, vol. 51, no.4 2007, pp. 531-567.

[26] Daniel Byman has noted that “the process by which the United States and other governments designate a terrorist sponsor is highly politicized, leading to poor conceptualization of the overall problem”; see Daniel Byman, Deadly Connections: States that Sponsor Terrorism. Cambridge, Cambridge University Press, 2005, p.4.

[27] It has been estimated that between 7 to 20% of the American soldiers fighting in Operation Enduring Freedom and Operation Iraqi Freedom can be diagnosed with PTSD, see IOM (Institute of Medicine), Treatment for Posttraumatic Stress Disorder in Military and Veteran Populations: Initial Assessment. Washington, D.C.: The National Academies Press, 2012. There is reason to believe this number might be even higher for returned foreign fighters, who lack good training or proper aftercare (two of the alleged mitigating factors).

[28] Holly G Prigerson, Paul K Maciejewski, and Roberta Rosenheck, “Population Attributable Fractions of Psychiatric Disorders and Behavioral Outcomes Associated with Combat Exposures among US Men,” Research and Practice 92, no. 1 (2002): pp.59–63.

[29] A new ICSR report is focusing specifically on the families of those who left to fight with IS. Shiraz Maher and Peter R Neumann, “Pain, Confusion, Anger, and Shame: The Stories of Islamic State Families,” London: ICSR, 2016.

[30] Jeanine de Roy van Zuijdewijn and Edwin Bakker, “Returning Western Foreign Fighters: The Case of Afghanistan, Bosnia and Somalia,” The Hague: ICCT, 2014. URL:

[31] David Shinn, “Al Shabaab’s Foreign Threat to Somalia,” Orbis 55, no. 2 (2011), p.208.

[32] Ibrahim Mohamed, “Somali Speaker Says Suicide Bomber Was Danish,” Reuters, December 11, 2009.

[33] Evan Kohlmann, Al-Qaida’s Jihad in Europe: The Afghan-Bosnian Network. Oxford: Berg, 2004, p.90.

[34] Petter Nesser, Islamist Terrorism in Europe, op. cit., p. 26.

[35] See for instance AFP, “Somali Shebab Extremists Kill Two of Their Own Chiefs: Spokesman,” Fox News, June 30, 2013.

[36] “United States of America V. Enaam M. Arnaout, Government’s Evidentiary Proffer Supporting the Admissibility of Coconspirator Statements, No. 02 CR 892,” 2003, 24. It must be noted, however, that it was not al-Qaida that was most strongly connected to the conflict. Al-Gama’a al-Islamiyya, led by Omar Abdel Rahman, and the Egyptian Islamic Jihad (EIJ) – at that time led by Ayman al-Zawahiri – were more prominently present; see J.M. Berger, Jihad Joe: Americans Who Go to War in the Name of Islam. Washington, D.C.: Potomac Books, Inc., 2011, p.55.

[37] Petter Nesser, “Chronology of Jihadism in Western Europe 1994–2007: Planned, Prepared, and Executed Terrorist Attacks,” Studies in Conflict & Terrorism 31, no. 10 (2008): p. 929.

[38] Frazer Egerton, Jihad in the West: The Rise of Militant Salafism. Cambridge: Cambridge University Press, 2011, p.121.

[39] Petter Nesser, Islamist Terrorism in Europe, op. cit. p. 37.

[40] Ibid.

[41] J.M. Berger, Jihad Joe, p.55.

[42] “Woolwich Murder Suspect: Michael Adebolajo Held in Kenya in 2010,” BBC News, May 26, 2013.

[43] Petter Nesser, Jihad in Europe: Patterns in Islamist terrorist cell formation and behaviour, 1995-2010. Oslo: University of Oslo, 2011, p.76.

[44] Thomas Hegghammer, “Abdullah Azzam, the Imam of Jihad” in: Gilles Kepel and Jean-Pierre Milelli, Al Qaeda in its own words. Cambridge, Massachusetts: The Belknap Press of Harvard University Press, 2008, p.81.

[45] Idem, p.101.

[46] Stéphane Lacroix, “Ayman al-Zawahiri, Veteran of Jihad” in: Gilles Kepel and Jean-Pierre Milelli, Al Qaeda in its own words. Cambridge, Massachusetts: The Belknap Press of Harvard University Press, 2008, p.154.

[47] S. Lacroix, “Ayman al-Zawahiri, Veteran of Jihad”, p.155.

[48] Fawaz A. Gerges, The Far Enemy: Why Jihad Went Global. Cambridge: Cambridge University Press, 2005, p.87.

[49] “Excerpts: ‘Al-Qaeda’ Call to Somalis,” BBC News, January 5, 2007.

[50] L. Vidino, R. Pantucci, and E. Kohlmann, “Bringing Global Jihad to the Horn of Africa: Al Shabaab, Western Fighters, and the Sacralization of the Somali Conflict”, op. cit., p. 222.

[51] Chris Hedges, “Muslims From Afar Joining ‘Holy War’ in Bosnia,” The New York Times, December 5, 1992.

[52] L. Vidino, R. Pantucci, and E. Kohlmann, “Bringing Global Jihad to the Horn of Africa: Al Shabaab, Western Fighters, and the Sacralization of the Somali Conflict”, op. cit., p.224.

[53] Thomas Hegghammer, Jihad in Saudi Arabia: Violence and Pan-Islamism Since 1979. Cambridge: Cambridge University Press, 2010, p.208.

[54] Damir Kaletovic and Anes Alic, “Al-Qaida’s Bosnian War Move,” International Relations and Security Network (ISN), March 28, 2008. URL:

[55] Idem, p.203.

[56] Jennifer Mustapha, “The Mujahideen in Bosnia: The Foreign Fighter as Cosmopolitan Citizen and/or Terrorist,” Citizenship Studies 17, no. 6-7 (2013), p.747.

[57] J.M. Berger, Jihad Joe: Americans Who Go to War in the Name of Islam, op. cit., p.90.

[58] Lorenzo Vidino, Al Qaeda in Europe: The New Battleground of International Jihad . Amherst: Prometheus Books, 2006, p.218.

[59] Idem, p.227.

[60] J. Mustapha, “The Mujahideen in Bosnia: The Foreign Fighter as Cosmopolitan Citizen And/or Terrorist,” op. cit., p.746.

[61] Stephanie Zosak, “Revoking Citizenship in the Name of Counterterrorism: The Citizenship Review Commission Violates Human Rights in Bosnia and Herzegovina Revoking Citizenship in the Name of Counterterrorism : The Citizenship Review Commission Violates Human Rights in Bosnia,” Northwestern Journal of International Human Rights 8, no. 2 (2010), p. 216.

[62] Alex Kroeger, “Bosnia’s Holy Warriors Ready to Fight Evictions,” The Guardian, July 23, 2000.

[63] J. Mustapha, “The Mujahideen in Bosnia: The Foreign Fighter as Cosmopolitan Citizen And/or Terrorist,” p.751.

[64] Idem. p.750.

[65] S. Zosak, “Revoking Citizenship in the Name of Counterterrorism”, op. cit., p.216.

[66] J. Mustapha, “The Mujahideen in Bosnia: The Foreign Fighter as Cosmopolitan Citizen And/or Terrorist,” p.750.

[67] S. Zosak, “Revoking Citizenship in the Name of Counterterrorism”, op. cit., p.216.

[68] US Embassy Sarajevo, “Bosnia–Abu Hamza, The CRC, And Extremists: A Case Study in Getting to Deportation,” January 16, 2008; URL:

[69] UK: Home Office, “Proscribed Terrorist Organisations”, July 15, 2016. URL: US: US Department of State, Foreign Terrorist Organizations, accessed on October 26, 2016; URL:

[70] Michael Taarnby and Lars Hallundbaek, Al-Shabaab: The Internationalization of Militant Islamism in Somalia and the Implications for Radicalisation Processes in Europe, 2010, p.39.

[71] Idem, p.6.

[72] Richard Norton-Taylor, “MI5 Chief Warns of Terror Threat from Britons Trained in Somalia,” The Guardian, September 26, 2010.

[73] Osman Ahmed, “Congressional Hearing To Testify At A Hearing Entitled: Violent Islamist Extremists: ‘Al Shabaab Recruitment In America,’” 2009.

[74] Goran Maunaga, “Bočinja Mirni Suživot Vehabija I Srba Povratnika,” Nezavisne, November 25, 2006.

[75] Franco Galdini, “From Syria to Bosnia: Memoirs of a Mujahid in Limbo,” Foreign Policy in Focus, December 19, 2013.

[76] Idem.

[77] US Embassy Sarajevo, “Bosnia: Abu Hamza Supporters Rally to Oppose Deportation,” 2008; URL:

[78] See e.g. Terence M. Keane et al. “Clinical evaluation of a measure to assess combat exposure”, Psychological Assessment: A Journal of Consulting and Clinical Psychology 1, no. 1 (1989), pp.53-55; IOM (Institute of Medicine), Treatment for Posttraumatic Stress Disorder in Military and Veteran Populations: Initial Assessment, 2012.

[79] IOM, Treatment for Posttraumatic Stress Disorder in Military and Veteran Populations: Initial Assessment, p.1.

[80] It needs mentioning that several thousands of foreign fighters – although only very few from Europe–have joined the side of the Assad-regime, and that the potential fallout of the presence of those fighters has remained virtually unstudied. However, given the topic of this special issue, this section will limit itself to the potential fallout linked to the foreign fighters who joined Sunni jihadi groups. For more on the Shiite fighters, see Phillip Smyth, “The Shiite Jihad in Syria and Its Regional Effects,”, The Washington Institute for Near East Policy, 2015.

[81] See for instance, Petter Nesser, Anne Stenersen and Emilie Oftedal in this Special Issue: Petter Nesser, Anne Stenersen and Emilie Oftedal, “Jihadi Terrorism in Europe: the IS-effect,” Perspectives on Terrorism 10(6).

[82] US State Department, “Worldwide Caution,” 2016; URL:

[83] Associated Press, “Isis Leader Encourages Lone Wolf Attacks on Civilians in Europe and US,” The Guardian, May 22, 2016.

[84] The exact decline is at the time of writing unclear; see Reuters, “Is the Number of Foreign Fighters Joining IS Really Plummeting?,” April 29, 2016.

[85] Please see Jakob Sheikh’s contribution in this Special Issue of Perspectives on Terrorism.

[86] Richard Barrett, The Islamic State, The Soufan Group, November 2014, p.9.; URL:

[87] “A Battle Much Larger Than the Islamic State,” The Soufan Group Intel Brief, October 18, 2016; URL:

[88] Adam Chandler, “Libya, ISIS, and the Flow of Foreign Fighters,” The Atlantic, March 11, 2016.

[89] Aaron Y. Zelin, “The War between ISIS and al-Qaeda for Supremacy of the Global Jihadist Movement,” The Washington Institute for Near East Policy, Research Notes, no. 20 (2014), p. 3.

[90] European Commission, “Special Eurobarometer 432: Europeans’ Attitudes Towards Security,” 2015.

[91] “The End of Tolerance? Anti-Muslim Movement Rattles Germany,” Der Spiegel, December 21, 2014.

[92] Jannis Grimm, “#We Are Not Charlie: Muslims’ Differentiated Reactions to the Paris Attacks, and the Dangers of Indiscriminate Finger-Pointing” SWP Commentary, no. February 2015 (2015): pp.1-8.

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