Jihadist mobilization in Europe is no novelty and has historically implied a range of activities: providing logistical and financial support to terrorist groups; planning and executing attacks; and travelling to war zones to join insurgent organizations and terrorist groups. For instance, during the 1990s, groups such as the Algerian Armed Islamic Group (GIA), the Egyptian al-Jama‘a al-Islamiyya, and the Libyan Islamic Fighting Group (LIFG) set up a network of supporters across European countries. Similarly, over the last decades European militants have joined jihadist groups in Afghanistan, Bosnia, Chechnya, Iraq, and Somalia.
However, jihadist mobilization has witnessed a sharp increase in recent years – especially after the outbreak of the Syrian conflict, in 2011, and the ascent of the Islamic State (IS), which proclaimed the caliphate on 29 June, 2014. On the one hand, the number of foreign fighters heading to Syria and Iraq is unprecedented, both from a European and worldwide perspective. Moreover, jihadist attacks in Europe – generally following a cyclical pattern, alternating relatively quiet periods and more violent ones – have experienced a spike.
This contribution will briefly illustrate the jihadist mobilization which has affected European countries over the last few years. In the first section, data on jihadism-related arrests, thwarted and executed attacks, and foreign fighters will be dissected. In the second part, the contribution will introduce the issue of young people’s involvement in jihadist terrorism, presenting data and examples. The third section will provide an overview of the reasons behind jihadist mobilization, with a particular focus on youth. Lastly, some final remarks will close the article.
Jihadist Mobilization in Europe: Some Data and Examples
To assess the jihadist mobilization across European countries in recent years – that is, the magnitude of jihadist activities carried out in the region –, various elements can be taken into account. Some useful indicators are provided by data on arrests, thwarted and executed attacks, and foreign fighters.
Arrests, Foiled Plots and Executed Attacks
In total, over the years 2012-2016, 2,175 suspects were arrested in EU countries for jihadist terrorism related offenses. This accounts for more than double the figure of the period 2006-2011, with 1,056 arrestees. In particular, the number of arrests has sharply increased after 2012: only 159 individuals were apprehended for jihadist terrorism in 2012, whereas that figure reached 718 individuals in 2016. However, the bulk of this rise occurred in the years 2013-2015, whereas the variation across 2015-2016 was less pronounced (687 arrests versus 718 arrests, respectively). A significant part of those arrests – more than half – occurred in France: 429 suspects were taken into custody in 2016, and 1,228 altogether over the years 2012-2016. A considerable amount of arrests occurred in Belgium, too.
Likewise, European countries witnessed a boost in the number of jihadist attacks perpetrated on their soil, especially after 2014. 46 terrorist attacks inspired by jihadist ideology were executed between 2014 and 2017 – nearly all of them between 2015-2017: 20 attacks in 2017, 14 in 2016, and 10 in 2015. To put things into perspective, it ought to be highlighted that between 2008-2013, 14 attacks have been carried out in Europe. Concerning the 2014-2017 wave, the most affected country was France – which saw 23 attacks on its territory since 2014 – followed by the United Kingdom and Germany (seven attacks in both cases), Belgium (four attacks), Austria, Denmark, Finland, Spain, and Sweden (one attack each). The terrorist operations resulted in a death toll of roughly 350 victims and over 2,000 injured. In parallel with launched attacks, a significant number of plots have been thwarted by authorities: for instance, over the period 2014-2016, 24 well-documented jihadist plots (and an even greater number of vague plans) were foiled.
Among the major halted plots, there was a terrorist plan envisioned by the so-called “Verviers cell,” dismantled in Belgium in January 2015. It apparently involved the use of TATP and semiautomatic weapons; although the intended target was not clear, it seemed that Brussels’ Zaventem Airport was an option. It was reportedly masterminded by Abdelhamid Abaaoud – a Belgian operative and key figure in the IS external operations branch (Amn al-kharji), who took part in the November 2015 Paris attacks. Another notable example was the Riviera bomb plot, foiled in February 2014 in the Cote d’Azur region, France. The suspect, Ibrahim Boudina, had allegedly trained with IS in Syria, and possibly contemplated targeting the Nice Carnival celebrations. He, too, appeared to have been dispatched back to France by IS.
The ultimate question of ‘why’ individuals (especially youngsters) become involved in jihadism-related activities has bedevilled policymakers, security services, scholars, and public opinions alike. All the more so because the path towards mobilization, implying a process of radicalization, is complex and multifarious, at the crossroads between personal factors and structural drivers, originating from a conducive environment. Thus, monocausal explanations are insufficient
With respect to attacks launched in 2014-2017, most of them (39 out of 46 attacks, i.e. nearly 85%) were carried out by single actors. While in most cases links between perpetrators and members of IS were rather weak, in a few instances a more substantial coordination can be spotted. The May 2014 shooting at the Brussels Jewish Museum is illustrative: Mehdi Nemmouche was initially thought to have acted alone; however, further investigations revealed that he had traveled to Syria and had been sent back to France by IS. Conversely, Mohamed Lahouaiej-Bouhlel – who killed 86 people in the July 2016 Nice attack – did not seemed to be connected with IS operatives, at least according to information disclosed so far. Another connection emerging in attacks of recent years is that of ‘virtual planning,’ where IS fighters assisted would-be jihadists outside of Syria and Iraq in preparing and committing attacks, by using social media and encrypted online messaging platforms. This is precisely what happened in the Wurzburg, Ansbach and Normandy church attacks, all executed in July 2016.
Only in seven cases out of 46 (i.e. roughly 15% of total 2014-2017 attacks), a group consisting of two or more actors physically took part in a terrorist act. However, the number of thwarted plots involving a group of militants is higher. This is possibly due to the fact that single-actor plots are less likely to be detected by authorities, in contrast with group-based plans. The (quite narrow) set of group-led attacks in 2014-2017 includes the November 2015 Paris attacks, the March 2016 Brussels attacks, and – more recently – the August 2017 Catalonia attacks.
Another phenomenon which mirrors the post-2011 jihadist mobilization is the flow of foreign fighters heading to Syria and Iraq. At a worldwide level, up to 40,000 individuals may have joined insurgent groups in the Syrian-Iraqi region. An unprecedented figure, indeed – and this holds true for European countries, too, although on a smaller scale. As a matter of fact, as many as 5,000 foreign fighters are estimated to hail from EU countries. The bulk of these foreign fighters enlisted in or supported extremist groups, especially the Islamic State – and this is why we refer to such figures to infer the magnitude of jihadist mobilization.
Departures of foreign fighters affected European countries in an uneven fashion. In absolute terms, France saw the largest number of ‘travellers’ (nearly 2,000), followed by Germany (over 900), the United Kingdom (850), and Belgium (around 480). In relative terms – that is, in comparison with each country’s population, Belgium ranks first (with 42 foreign fighters per one million inhabitants), followed by Austria and Sweden (34 and 31 foreign fighters per one million inhabitants, respectively). Instead, Southern European countries such as Spain and Italy produce a modest contingent, both in absolute and relative terms: 204 and 129 foreign fighters, respectively, which means four and two ‘travellers’ per one million people. The number of foreign fighters is even smaller in eastern European countries: for instance, as of April 2016, Estonia and Latvia witnessed the departure of just two individuals each.
A common fear relating to foreign fighters has to do with the so-called ‘blowback effect’ – namely, the risk that a number of combatants may return to their home countries to conduct a terrorist attack. This threat was highlighted by Europol as early as 2012: mujahidin may take advantage of the training, the experience, the knowledge and the contacts acquired at the front to strike at home. Such concerns are not unfounded: in recent years, jihadist veterans took part in various attacks worldwide, including the November 2015 Paris attacks and the March 2016 Brussels attacks. Another example is provided by Rachid Redouane, one of the June 2017 London Bridge attackers, who had reportedly fought in Libya. Returnees may also be involved in auxiliary activities – logistically and/or financially assisting other cells, as well as acting as ‘radicalizing agents’ vis-à-vis other members of their community. What is more, the Islamic State endured massive territorial losses over the last year, with the risk that an increasing number of jihadist combatants and supporters may return to their countries of origin. Apparently, indeed, 30% of European foreign fighters have already returned home. Nonetheless, various factors mitigate this kind of threat. In the first place, it would be misleading to equate fighting abroad with the execution of terrorist attacks at home. Not all foreign combatants will head back home, and even returnees may not intend to target their countries of origin. As shown in a study by Hegghammer – which focuses on waves of Western foreign fighters from 1990 to 2010 – only one out of nine returned to carry out an attack in their country of origin. In the period 2014-2017, 15 out of 66 perpetrators (23%) were jihadist veterans.
The Reasons Behind Jihadist Mobilization and the Role of Youngsters
Youngsters as the Bulk of Jihadist Mobilization
While there is no common jihadist profile – with huge differences in socio-demographic variables such as age, gender, education, and economic conditions – a few recurring patterns can be pinpointed, one of them being the relatively young age of jihadist attackers and foreign fighters. When analyzing attacks carried out in European countries between 2014 and 2017, it emerges that the average age of perpetrators is roughly 27.5 years. The mode, i.e. the most recurring age, is 29, while the median, i.e. the ‘central’ value, is 27; moreover, the youngest attacker was 15 years old at the time of the terrorist act, whereas the oldest was 54. Indeed, only six out of 66 perpetrators (accounting for 9%) were underage at the time of the attack; 20 individuals (30%) were in the 18-24 bracket; 20 (30%) were in the 25-30 bracket, and, finally, 18 (27%) were over 30 years old.
Two (opposite) aspects can be observed. For one thing, individuals aged 30 and younger account for the vast majority (nearly 70%) of perpetrators in Europe in the last four years. For example, the jihadists who physically carried out the August 2017 Catalonia attacks were all under 25, and one of them, Moussa Oukabir, was underage at the time. Likewise, both Adel Kermiche and Abdel Malik Petitjean, who carried out the July 2016 Normandy church attack, were 19 years old. Even more striking is the case of Yusuf K., a 15-year-old teenager who in January 2016 assailed a Jewish teacher in Marseille, wielding a machete. These incidents seem to be consistent with a pattern already underscored by media and academia alike – i.e. the growing number of increasingly young would-be jihadists. This trend, however, does not always hold true, and may even be contradicted in a few cases. Suffice it to say that the proportion of attackers over 30 – 27% – is far from negligible. In two occurrences – the March 2017 Westminster attack and the June 2017 Linz stabbing – attackers were in their 50s. Not to mention that the average age of European perpetrators (27.5 years), though under 30, is not exceptionally young.
Similar remarks can be made as regards foreign fighters from European countries. The European contingent is highly diversified – so generalizations would be ill-suited –, but it is possible to spot some recurrent age patterns. In this case, too, young men between 18 and mid-to-late twenties (at the time of their departure) are overrepresented, with differences across countries. In a few eastern and southern European countries, foreign fighters tend to be older. For instance, Italy – whose ‘travellers’ are mostly (47%) 30 years old or younger – also displays a significant proportion of individuals over 30 (40%).
Jihadist Mobilization: What Are the Drivers?
The ultimate question of ‘why’ individuals (especially youngsters) become involved in jihadism-related activities – be it in the form of preparing attacks at home or joining groups abroad – has bedevilled policy-makers, security services, scholars, and public opinions alike. All the more so because the path towards mobilization, implying a process of radicalization, is complex and multifarious, at the crossroads between personal factors and structural drivers, originating from a conducive environment. Thus, monocausal explanations are, at best, insufficient – if not misleading – when trying to understand the radicalization and mobilization of jihadist sympathizers. A thorough analysis of the issue would require much more space, beyond the scope of this article. Here, we will introduce only the main hypotheses.
Potential motivations behind jihadists’ paths of radicalization and mobilization can be roughly divided into two sets: individual-related and contextual-related factors. Among the individual-related drivers, socio-economic factors are one of the most recurring explanations. This hypothesis concerns the marginalization of Muslim communities (meaning a lack of integration, scant access to education, jobs, and opportunities, but also a general sense of disenfranchisement) as the main factor at the root of radicalization. In this respect, a few points are worth highlighting. First of all, when analyzing the radicalization and mobilization of jihadists in Europe, it is essential to devote attention to social conditions: failing to do so would imply missing a (critical) piece of the puzzle. Yet, focusing solely on this aspect risks delivering an incomplete picture, too; as we will see, other crucial elements should be taken into account. Not every terrorist incident can be explained with the poverty-extremism hypothesis. Secondly, the existence of a straightforward, explicit link between deprivation and extremism has proved to be uncertain, with significant variation across geographical areas. In the case of Europe – as observes Hegghammer – while it is true that jihadists, on average, tend to be economic underperformers, correlation is not tantamount to causation. The true question relates to the extent of this causal link and its interplay with other factors.
Other kinds of individual-related factors have been underlined, including personal frustrations experienced by people at some moment in their lives, often youngsters. Interestingly, Oliver Roy proposed an alternative interpretation, focusing on the young, especially second-generation Muslims. In his view, it makes sense to speak of the ‘Islamization of radicalism’: some of these youngsters – feeling alienated in Western societies, and at the same time experiencing a generational revolt against their families – frame this sense of rebellion and nihilism in jihadist terms. Thus, Roy asserts, the real issue is that these individuals are in search of an extremist cause to embrace, while they overlook the religious dimension proper.
With reference to context-related drivers, a variety of pull factors prompted the mobilization of European foreign fighters towards Syria and Iraq. The two most prominent triggers were possibly the outbreak of the Syrian conflict in 2011 (and the ensuing violence), as well as the proclamation of the caliphate by IS, on 29 June, 2014. As a matter of fact, numerous militants were motivated by the desire to fight the Assad regime and defend local Muslims, considered to be under siege. After the establishment of the ‘caliphate’ was announced, further (personal) motivations came into play: the epic narrative nurtured by IS and its members; adventurism and the wish to evade reality; jihadist sympathizers’ eagerness to live in a context where – they thought – Islamic tenets were strictly implemented. On top of that, the Syrian-Iraqi area had been relatively easy to reach for a significant amount of time.
Lastly, another context-related variable has to be addressed: radicalization hubs and how they affect jihadist mobilization, not just in terms of foreign fighters’ departures, but also in terms of preparing attacks. The hub model can complement other interpretations, offering an explanation for geographical discrepancies which – on the surface – seem beyond comprehension. Actually, the intensity of jihadist activities not only varies across countries, but even within a given country. A particular town, for instance, may stand out for its unusually high number of jihadist sympathizers and militants – in spite of sharing virtually identical social, economic, and demographic indicators with nearby towns and cities. In this case, the dynamics of hubs may well be at work.
Why and how these clusters emerge and solidify is more difficult to ascertain – usually due to an interplay of diverse factors. Among them, there is the presence of a ‘radicalizing agent’ (such as a charismatic preacher or a jihadist veteran), but also kinship and friendship bonds play a huge role. The August 2017 Catalonia attacks are telling: it is suspected that Imam Es Satty – the ringleader, older than the other plotters and arguably more experienced and familiar with the jihadist milieu – acted as a radicalizing agent, while pre-existing ties between the other members of the cell would do the rest. In other instances, the particular condition of a certain area (e.g. high rate of crime, social exclusion, etc.) may provide a conducive environment for the rise of jihadist hubs. In some circumstances, fortuity may be involved, too. The case of Lunel, a French town which is home to less than 30,000 people, and – puzzlingly – ‘produced’ some twenty foreign fighters, is illustrative in this respect.
To Sum Up: Conclusive Remarks
This brief contribution aimed to outline the development of jihadist activities in Europe in recent years. As already seen, the outbreak of the Syrian conflict and the ascent of IS marked a spike in domestic mobilization – a fact which is mirrored by the sheer number of arrests, thwarted plots, launched attacks, and foreign fighter flows. Jihadist mobilization, nonetheless, hit European countries unevenly. The most affected country – in relation to arrests, attacks, and foreign fighter departures alike – was France. Countries like Germany, the United Kingdom, and Belgium have, too, been significantly affected by the phenomenon. Other nations, however, – first and foremost eastern European countries – saw a rather low degree of mobilization.
Understanding the exact triggers which activate radicalization and mobilization is no smooth task. A plethora of factors, indeed, feature in this complex equation – both personal, individual reasons and structural causes, originating from an enabling environment. Volatility and violence in the Levantine region and the rise of IS are arguably two relevant, context-related factors. As concerns individual-related drivers, the picture becomes increasingly complex, also implying more subjective reasons (personal frustrations, for examples) linked to very specific life events experienced by single individuals. Social and economic conditions are typically cited as potential trigger factors. Oliver Roy, then, frames the radicalization of disenfranchised youngsters as a generational revolt and an ‘Islamization of radicalism.’ Finally, speaking of ‘jihadist hubs’ may help explain idiosyncratic concentrations of jihadists in a certain geographical area.
The outbreak of the Syrian conflict and the ascent of IS marked a spike in domestic mobilization – a fact which is mirrored by the sheer number of arrests, thwarted plots, launched attacks, and foreign fighter flows
Regrettably, the debate on jihadism in Europe has too often been portrayed in a simplistic fashion, with a binary approach. On the one hand, oversimplifications and single-cause explanations have been put forth – but, as such, they cannot capture the complexity of the phenomenon, and end up catering to a flawed picture. On the other hand, the different hypotheses have been treated as mutually exclusive explanations – yet it is not always the case. In the future, it may be beneficial to explore intersections between the different explanatory models. If it is true that a number of European jihadists endure social and economic marginalization, then under what conditions may poverty and exclusion lead to extremism? And under those circumstances, can other factors (e.g. the presence of radicalizing agents) activate a process of radicalization? If so, how? Answering those questions requires building a more comprehensive, multidimensional explanatory frame – and this is a prerequisite for better understanding the untangled phenomena that are radicalization and mobilization.
 We define foreign fighters as “non-citizens of conflict states who join insurgencies during civil conflicts” (D. Malet. Foreign Fighters: Transnational Identity in Civil Conflicts. New York: Oxford University Press, 2013, p. 9)
 When speaking of ‘Europe’ and ‘European countries,’ we generally refer to EU countries (plus Norway and Switzerland, in some cases). Therefore, the Balkans, Turkey, Russia, and former Soviet republics are excluded.
 Please note that these figures do not take into account the UK, since the data provided by the country do not disaggregate terrorist incidents by ideology (jihadist, left-wing, right-wing, etc.)
 Europol, EU Terrorism Situation & Trend Report (TE-SAT), TE-SAT 2009; TE-SAT 2013; TE-SAT 2014; TE-SAT 2015; TE-SAT 2016; TE-SAT 2017, www.europol.europa.eu/activities-services/main-reports/eu-terrorism-situation-and-trend-report#fndtn-tabs-0-bottom-2
 Nesser Petter, Stenersen Anne, and Oftedal Emilie. “Jihadi Terrorism in Europe: The IS-Effect.” Perspectives on Terrorism 10(6); ISPI Database on Jihadist Attacks in the West.
 Nesser Petter, Stenersen Anne, and Oftedal Emilie. “Jihadi Terrorism in Europe: The IS-Effect,” cit.; ISPI Database on Jihadist Attacks in the West.
 Barrett Richard. “Beyond the Caliphate: Foreign Fighters and the Threat of Returnees.” The Soufan Group, 2017, http://thesoufancenter.org/wp-content/uploads/2017/10/Beyond-the-Caliphate-Foreign-Fighters-and-the-Threat-of-Returnees-TSC-Report-October-2017.pdf passim; Eurostat (2016), http://appsso.eurostat.ec.europa.eu/nui/show.do?dataset=demo_pjan&lang=en; Il Sole 24 Ore, “Sicurezza, il Viminale: nel 2017 -34% sbarchi, più espulsi per terrorismo,” 31 December, 2017, URL: www.ilsole24ore.com/art/notizie/2017-12-31/sicurezza-viminale-2017-34percento-sbarchi-piu-espulsi-terrorismo-161344.shtml?uuid=AEGptOZD&refresh_ce=1
 Barrett Richard. Op.cit p. 10.
 Hegghammer Thomas, “Should I Stay or Should I Go? Explaining Variation in Western Jihadists’ Choice between Domestic and Foreign Fighting,” American Political Science Review 107(1), 2013, p. 10.
 ISPI Database on Jihadist Attacks in the West.
 The age of two attackers is unknown.
 Thus excluding those who provided support and/or intended to strike, but actually did not take part in the attack (e.g. Imam Es Satty). The included perpetrators are: Younes Abouyaaqoub; Houssaine Abouyaaqoub; Omar Hichamy; Mohamed Hichamy; Moussa Oukabir; Said Aallaa.
 ISPI Database on Jihadist Attacks in the West.
 Van Ginkel Bibi and ed Entenmann Eva (ed.). “The Foreign Fighters Phenomenon in the European Union. Profiles, Threats & Policies.” The International Centre for Counter-Terrorism: The Hague, 2016, p. 51.
 ISPI Database on Italian Foreign Fighters. In 13% of cases, the age is unknown.
 Hegghammer Thomas, “Revisiting the poverty-terrorism link in European jihadism.” Lecture before the Society for Terrorism Research’s annual conference, Leiden, 8 November, 2016; Vidino Lorenzo, Marone Francesco, and Entenmann Eva. Fear Thy Neighbor: Radicalization and Jihadist Attacks in the West. Institute for International Political Studies. Milano: Ledizioni, 2017, pp. 78 ss.
See Roy Olivier. Le Djihad et la mort. Paris: Seuil, 2016.
 Vidino Lorenzo, Marone Francesco, and Entenmann Eva. Fear Thy Neighbor: Radicalization and Jihadist Attacks in the West, cit., pp. 82 ss.