#ReaCT2025 – Jihadist Terrorism in Europe: what the numbers tell us
Historical Trajectories, Social Dynamics, and Opera-tional Transformations in the Current Phase of Global Change.
by Claudio Bertolotti, START InSight, Director
This article was published in #ReaCT2025, the annual Report on Terrorism and Radicalisation
Terrorism as a political and social phenomenon that evolves over time, in step with shifting dynamics of competition among individuals, groups, and states. Contemporary terrorism is not a historical exception; it is the outcome of a long accumulation of conflicts, doctrines, and opportunities. Over the past twenty years in particular, we have witnessed an evolution that has repeatedly changed shape without losing its core function: generating fear, polarisation, and socio-political conditioning with a relatively limited investment. After 9/11, jihadist terrorism acquired a globalised and “systemic” dimension, anchored in transnational networks and in a narrative able to link war, identity, ideology, and political pragmatism. The subsequent phase – marked by Iraq and Afghanistan – turned violence into operational experience and symbolic capital: insurgency, terrorism as technique, tactic, and procedure, and communication as a force multiplier ultimately merged. With the rise of the Islamic State between 2014 and 2017, we saw the shift to a hybrid model: territorial organisation and external projection, commando-style teams and lone actors, coordinated attacks and improvised micro-actions. The contraction of the “caliphate” did not mean the phenomenon’s defeat, but rather its reconfiguration: greater fragmentation, more emulation, and stronger individual initiative.
Within this framework, the jihadist threat remains particularly significant because it intersects with the conflict dynamics of international relations and competition in the Middle East and Africa, and because it draws on a radical reading of Islam that turns political events into moral pretexts, cloaking them in religious justification. It becomes even more sensitive in Europe when it grafts onto an individual and group search for identity, fuelled by the cultural opposition of a non-marginal segment of second- and third-generation Maghrebi immigrant communities: a terrain where belonging is also constructed “against” the other, and where polarisation functions as a risk multiplier.
We are not, in fact, dealing with a monolithic bloc. Today the jihadist galaxy is fragmented: ideologies, operational priorities, and modes of action diverge, which compels us to read contemporary terrorism also as a social phenomenon, not merely as the expression of clandestine organisations. Forms change, but above all the mechanisms through which violence is produced change: faster activation timelines, lower operational thresholds, and greater permeability to emulation and media-triggered mobilisation.
From this follows a reflection that, after two decades of adaptations, can no longer be postponed – and one we continue to insist upon: does it still make sense to define terrorism solely as violence aimed at achieving a political result, assessed therefore in terms of intent? Or is it more useful to read it as the effect of applied violence – namely, as a manifestation capable of generating impact regardless of the chain of command? In other words: is the violent act itself terrorism, even when there is no organisation behind it, or when such an organisation cannot be demonstrated? The centre of gravity shifts, then, from structure to event: terrorism in its manifestation, not necessarily in its organisation.
Within the jihadist galaxy, terrorism remains an instrument of struggle, resistance, and domination, but it unfolds along a spectrum of violence that ranges from individual action to organised operations; from inspired violence to emulative violence; up to the insurgent terrorism we have come to know in Afghanistan and Iraq and that, in part, we observe in its manifestations in the Gaza Strip, where the Israeli army confronts Hamas (Bertolotti, 2024a). In this perspective, continuity lies not in the form of the attack, but in its function: compressing security and freedom, pushing the state to react, and turning social fracture into operational space.
Trends and dynamics: numbers are declining, but the terrorist threat persists – an analysis of attacks from 2014 to 2025.
From a quantitative standpoint, jihadist terrorist attacks over the past five years confirm a broadly linear trend, with a noticeable decline in the most recent years, bringing the phenomenon back to pre-ISIS/Islamic State levels. Between 2020 and 2025, 99 successful and failed attacks were recorded across the European Union, the United Kingdom, and Switzerland (12 in 2025). The same total – 99 – was observed in the previous period 2014–2018 (12 in 2015).
In the wake of the phase of major attacks in Europe carried out in the name of the Islamic State and, subsequently, in plausible connection with galvanising factors triggered by the Taliban’s seizure of power in Afghanistan and by Hamas’s call to action, 221 jihad-related incidents were recorded between 2014 and 2023. Of these, 77 were attributable to the Islamic State. A total of 271 terrorists took part (7 women), 78 of whom were killed during the attacks. Overall, the toll amounts to 457 fatalities and 2,667 wounded (START InSight database).
In 2025 alone, 12 jihadist incidents were recorded: a slight decrease compared with the previous year (15 attacks in 2024), consistent with the 12 attacks recorded in 2023, yet clearly below the 18 registered in both 2022 and 2021. This numerical reduction, however, does not translate into lower risk. The share of “emulative” ac-tions – those inspired by attacks carried out in the immediately preceding days – rises sharply. Emulation increases from 17% of all incidents in 2022 to 58% in 2023 (56% in 2021) and reaches 50% in 2025, bringing the phenomenon back to intensity levels comparable to those of earlier years.
2025 also consolidates a structural trend in the evolution of the threat, marked by the predominance of individual, non-organised, and often improvised attacks, which have progressively replaced the structured and coordinated operations typical of the European urban “battlefield” in 2015–2017. This operational model accounted for 92% of incidents in 2025, while also showing a renewed use of vehicle-ramming tactics against civilian targets – mainly pedestrians – in 17% of cases.
The profile of “European” terrorists.
Jihadism, according to the data, continues to appear as a phenomenon with predominantly male participation. Of the 329 perpetrators recorded, 94% are male; women number 10. The picture is also dynamic: while 2020 saw 3 female attackers involved in terrorist actions, no direct female participation emerges in the five-year period 2021–2025.
From a demographic perspective, identified terrorists (men and women) for whom public personal data are available show a median age of 26. This value fluctuates over time: 24 in 2016, 30 in 2019, then rising in the latest observed phase to 28.5 in 2023 and, strikingly, 35 in 2025 – thereby indicating an increase in perpetrators’ age. Looking more closely at the 200 individuals for whom sufficiently detailed biographical information is available, the age distribution provides a more nuanced profile: 7% are under 19 (with the weight of minors declining over time), 38% fall within the 19–26 bracket, 41.5% within 27–35, and 13.5% are over 35. Overall, these data suggest a gradual upward shift in average age within the 19–35 segment, with a notable increase in the over-35 cohort, alongside a contraction in the share of minors involved in attacks over the same time span.
As to legal status and origins, the prevailing profile of perpetrators falls within the broad category of “immigrants” (first, second, and third generation), both regular and irregular: 93% of individuals who carried out a terrorist act. In the subset analysed through the START InSight database (155 cases out of 237 terrorists), 45% are regular first-generation immigrants; 28% are descendants of immigrants (second or third generation); and irregular immigrants account for 26%. The latter figure, however, is the one that signals the sharpest discontinuity: it stands at 25% in 2020, doubles to 50% in 2021, reaches 67% in 2023, and then settles at 31% in 2025. The trend confirms a growing presence of first-generation perpetrators; also noteworthy is the 6% share of European-origin citizens who converted to Islam, showing a steady – albeit slight – decline compared to previous years’ averages.
The ethno-national dimension of terrorists in Europe.
In Europe, jihadist radicalisation does not affect populations uniformly; it tends to concentrate within specific national and ethnic components. The data confirm a fairly clear proportional relationship between the composition of major migrant groups and the (direct or familial) background of those who commit terrorist acts: the nationality of terrorists, or that of their families of origin, often mirrors the size and historical rootedness of foreign communities within individual European countries. Within this framework, Maghrebi origins predominate. The ethno-national groups most associated with jihadist adherence remain Moroccan (with significant evidence in France, Belgium, Spain, and Italy) and Algerian (in France). Unsurprisingly, the phenomenon appears more pronounced in Belgium and France, where large Moroccan and Algerian-origin communities have, over time, recorded high levels of youth mobilisation toward jihadist milieus and organisations. In France, for example, a substantial share of terrorists involved in recent attacks comes from families of Algerian and Moroccan origin, consistent with the historical presence and numerical weight of these communities in the country (Bertolotti, 2023 and 2024).
Recidivists and terrorists already known to intelligence.
A second, increasingly relevant indicator concerns the significance of recidivism, also as a consequence of releases at the end of recently completed prison sentences. These are individuals previously convicted of terrorism who strike again after leaving prison and, in some cases, manage to carry out violent actions even within detention facilities. The trajectory is clear: recidivists account for 3% of all terrorists who struck in 2018 (1 case), 7% in 2019 (2), 27% in 2020 (6), 25% in 2023 (3), then falling to 8% in 2025 (1). Although clearly declining, the figure confirms the social dangerousness of individuals who – while temporarily neutralised through detention – often do not abandon the intent to act; rather, they postpone it, waiting for a more favourable operational window. Prospectively, this would imply a higher probability of attacks in the coming years, alongside the release of a growing number of inmates convicted of terrorism offences.
Further reinforcing this picture, START InSight also highlights the tendency for terrorist acts to be carried out by individuals already known to European law enforcement or intelligence services. In 2020 such cases represent 54% of the total, and 44% in 2021, 37% in 2022 – figures well above the 10% recorded in 2019 and 17% in 2018. In 2023 the figure rises further and stabilises at 75%, effectively confirming the concerns of institutions tasked with countering the threat, although 2025 ended with a more reassuring figure of 23%.
Finally, the profile of individuals with prior detention records (including for offences unrelated to terrorism) shows significant continuity across the period considered: 23% in 2021, slightly down from 33% in 2020, but consistent with 23% in 2019 (28% in 2018 and 12% in 2017). Even in light of a markedly lower 2023 figure (8%) and a near-zero level in 2025, the overall evidence continues to support the hypothesis that detention settings remain risk environments where radicalisation and adherence to terrorism may find enabling conditions.
What is the terrorist threat’s real destructive capacity?
To read terrorism realistically, it must be broken down – without conflating different planes – into three levels: strategic, operational, and tactical. The strategic dimension concerns the use of resources to achieve long-term objectives, those that shape the overall configuration of a conflict and influence state behaviour. The tactical dimension, by contrast, relates to the use of force in the single “engagement” to secure an immediate, circumscribed result. Between the two sits the operational level: the hinge that coordinates, sequences, and combines tactical actions in order to generate effects consistent with the strategic objective. This distinction is essential because, in terrorism, what may appear “small” at the tactical level can be decisive operationally and only marginal strategically. Ultimately, this lens brings the employment of people – more than platforms or means – back to the centre of how military and political effects are produced.
Strategic success: marginal and receding.
At the strategic level, the success of terrorist actions – understood as the ability to generate structural, systemic outcomes (disruption of national and/or international air or rail traffic, mobilisation of armed forces, wide-ranging legislative measures) – tends to disappear over time. The historical pattern shows a progressive erosion in the ability to achieve strategic effects, with fluctuations but a clear trajectory: 75% strategic success in 2014; 42% in 2015; 17% in 2016; 28% in 2017; 4% in 2018; 5% in 2019; 12% in 2020; 6% in 2021. From 2022 onwards, attacks no longer manage to achieve strategic success. Past strategic success remains noteworthy when set against the low organisational and financial investment required, especially where actions are individual or low-complexity.
In parallel, overall media attention to attacks has declined. At the strategic level, attacks received international media attention in 70% of cases and national media attention in 93%. Commando-style operations and team-raids, when present, attracted full coverage. This “media success” may have had a direct impact on recruiting would-be martyrs or jihadist fighters, peaking during the periods of highest intensity of violence (2016–2017). Yet the media’s amplifier effect on recruitment tends to diminish over time for two converging reasons. First, there has been a progressive predominance of “low-intensity” actions over “high-intensity” ones: the latter have declined, while low- and medium-intensity actions increased significantly from 2017 to 2021, alongside a marked rise in medium-intensity actions in 2023 (75%) and in 2025 (58%), and a renewed uptick in “high-intensity” actions in 2025 (8%). Second, the public’s gradual emotional desensitisation to terrorist violence – especially in relation to low- and “medium-intensity” events – reduces an attack’s capacity to dominate the information space.
The tactical level: concerning, but not central to terrorism’s logic.
If we take as the primary tactical goal the death of the “enemy” – with security forces identified as the target in 28% of cases – this outcome is achieved, on average, in 48% of cases over the period 2004–2025. However, such a broad time horizon significantly increases the margin of error. Focusing on 2014–2025, a deterioration in the capacity to produce the intended effect becomes apparent: low-intensity attacks predominate and failed actions increase, at least until 2022, when tactical success stabilises at 33%, consistent with the 2016 figure. From 2023 onward, by contrast, a reversal in trend is recorded.
Over the last six years, the pattern is particularly illustrative. In 2016, tactical success stands at 31%, with 6% failed acts. In 2017, success rises to 40%, while failure reaches 20%. In 2018, success drops to 33% and failed attacks double to 42%. In 2019, success falls further to 25%, then rebounds and stabilises at 33% in 2020–2022. This trajectory can be read as the combined effect of a reduction in terrorists’ operational capability and the increased responsiveness of European security forces. Although in 2023 the figure returns to 50% of actions achieving tactical success – namely, the death of at least one target – in 2024 and 2025 it drops back to earlier levels, with 20–25% tactical successes.
The real outcome: operational success and “functional blockade”.
The decisive point is that even an “unsuccessful” attack, in terms of producing fatalities, can still generate a significant operational result. Terrorist action tends to saturate and constrain resources (Bertolotti, 2023, 2024): it heavily engages armed forces and police, diverting them from routine activity or limiting their capacity to intervene on behalf of the wider community. It can disrupt or overwhelm health services; restrict, slow, divert, or halt urban, air, and maritime mobility; and hinder the normal conduct of daily, commercial, and professional activities, with a direct impact on the communities affected. In doing so, it reduces technological advantage and overall operational potential and compresses resilience. The damage may be direct or indirect and can manifest even in the absence of victims. Above all, it produces a measurable effect: the restriction of citizens’ freedom.
From this perspective, terrorism’s success – even when it does not kill – lies in its ability to impose economic and social costs on society and to shape behaviour over time, in relation to security measures and the constraints introduced by political and public-security authorities. This is what we define as “functional blockade”. Despite the progressive reduction in operational capability, “functional blockade” remains one of the most significant outcomes achieved by terrorists, irrespective of tactical success (the killing of at least one target). From 2004 to the present, terrorism has proven effective in achieving “functional blockade” in 80% of cases, peaking at 92% in 2020 and 89% in 2021. This is a notable result, attained with limited resources, confirming a cost–benefit ratio favourable to terrorism. Yet here too a progressive loss of capability is evident: the achievement of “functional blockade” drops to 78% in 2022, to 67% in 2023, and to 58% in 2025.
Bibliography
Bertolotti, C. (2024a), Gaza Underground: la guerra sotterranea e urbana tra Israele e Hamas. Storia, strategie, tattiche, guerra cognitiva e intelligenza artificiale, START InSight ed., Lugano.
Bertolotti, C. (2024b), Una fotografia del terrorismo jihadista in Europa: evoluzione storica e operativa, in #ReaCT2024, 5° Rapporto sul Terrorismo e il Radicalismo in Europa, START InSight ed., Lugano, ISBN 978-88-322-94-27-9, ISSN 2813-1037 (print), ISSN 2813-1045 (online).
Bertolotti, C. (2023), L’evoluzione del terrorismo in Europa: terrorismo di sinistra, destra, anarchico, individuale, e il ruolo degli immigrati nel terrorismo jihadista all’interno dell’Unione Europea (Analisi di correlazione e regressione), in #ReaCT2023, 4° Rapporto sul Terrorismo e il Radicalismo in Europa, START InSight ed., Lugano, ISBN 978-88-322-94-18-7, ISSN 2813-1037 (print), ISSN 2813-1045 (online).
