Migration and Islamist terrorism: what the data shows

The short answer. Some of Europe's deadliest recent Islamist attacks were carried out by men who arrived as asylum seekers, and several of them had already been refused asylum or ordered to leave. Others were carried out by citizens born and raised in Europe. Europol counted 24 jihadist attacks in the EU in 2025, nine of them completed, and 347 arrests for jihadist offences.⁸ It has never published how many attackers or suspects were asylum seekers. Where it splits suspects by citizenship, EU citizens are the larger group.⁵⁶

The attackers described on this page were Muslims, or converts to Islam, who became radicalised and acted for a violent ideology, usually that of Islamic State. Most Muslims and most migrants are not extremists, and jihadists treat Muslims who reject them as enemies.⁷

Key facts #

• 2025. EU states reported 24 jihadist attacks to Europol: nine completed and 15 foiled. The completed attacks killed five people. All nine were carried out by lone men, eight of them with knives.⁸
• Arrests. Police in the EU arrested 347 people for jihadist offences in 2025, out of 486 terrorism arrests of all kinds. 108 of the 347 were aged 18 or younger.⁸
• 2020. Of ten completed jihadist attacks in the EU, five were by people who had entered as asylum seekers or irregular migrants, four of them years earlier. Four were by EU citizens.³
• Germany since 2020. A study in the CTC Sentinel found that eight of the nine attackers in completed Islamist attacks in Germany from 2020 to May 2025 had come through the asylum or refugee system.⁵¹
• Long-run Europe. A 2025 ICCT study of 55 people behind 43 jihadist attacks in the EU from 2014 to 2024 found that most were born in Europe or had lived there for more than five years. Five attacked within a year of arriving.⁴⁹
• Removal failures. The attackers in Berlin (2016), Hamburg (2017), Brussels (2023), Solingen (2024), Munich (2025) and Mulhouse (2025) had all been refused asylum, ordered to leave or due to be transferred, and were still in the country.^111216181921
• Citizens. The Manchester Arena bomber (2017) was born in Britain, and the Berlin Pride attacker of July 2026 was a German citizen born in Germany.²⁵²⁷
• United States. Of 16 lethal jihadist attackers in the US after 9/11, nine were US-born citizens, according to New America.³⁰

What does Europol say about migrants and terrorism? #

Europol has said for ten years that terrorist groups have used migration routes in a few cases, and that this has not been systematic. Europol is the EU's police agency. Its yearly Terrorism Situation and Trend Report (TE-SAT) reports what member states tell it. Each report covers the year before.

• 2015. Two of the bombers at the Stade de France on 13 November 2015 had been registered on the Greek island of Leros a month earlier, travelling with refugees on false Syrian passports.⁹ Europol said the Paris attack cell used the irregular migration flow to send operatives into Europe.¹
• 2016. The Netherlands reported Islamic State operatives applying for asylum, and Switzerland investigated three men posing as Syrian refugees.¹
• 2017. Europol said terrorist use of the migrant flow had been seen but was "not deemed systematic". Austria, Greece and Italy found no evidence of organised smuggling of terrorists.²
• 2020. Five of the ten completed attacks were by people who had entered as asylum seekers or irregular migrants. In four of the five they had lived in the EU for several years, and Europol said several "seem to have become radicalised in Europe".³
• 2025. All nine completed attacks were by lone actors. Europol names online platforms as the main route into radicalisation, often fast and often among teenagers.⁸

What Europol publishes on suspects' citizenship #

Europol does not publish a yearly count of suspects by asylum status. It gives citizenship splits in some years, with many suspects of unknown status.

"Non-EU citizen" covers students, workers, long-term residents and irregular migrants as well as asylum seekers. The years are not directly comparable, because the share of suspects with known status changes.

Which attackers in Europe were asylum seekers or recent migrants? #

These are attacks that prosecutors or courts treated as Islamist, where the attacker's status was reported by an official source or a major news outlet. It is a list of notable cases, not a sample, so it cannot be used to work out a share.

Three recurring problems stand out. Refused applicants were not removed, either because their home country would not take them back or because a transfer deadline passed. People who arrived as minors had strong legal protection from removal. And several men radicalised years after they arrived: the Dresden attacker in prison, the Villach attacker online in 2024.³²⁰

Cases often cited that were not ruled Islamist #

Some attacks are cited in this debate but were not treated as Islamist terrorism. At Aschaffenburg in January 2025 an Afghan whose asylum claim had been refused killed two people, including a two-year-old boy; a court found him not criminally responsible because of paranoid schizophrenia.²⁴ The Magdeburg Christmas market attacker of December 2024 was a Saudi-born refugee whose stated grievances were not Islamist; prosecutors did not treat it as terrorism.

Which attackers were citizens born or raised in Europe? #

Many of the deadliest attacks were carried out by citizens.

Researchers have found the same pattern over longer periods. A 2017 study of 65 attackers in Europe and North America from mid-2014 to mid-2017 found that 73% were citizens of the country they attacked, 14% were legal residents or visitors, and 5% (three people) were refugees or asylum seekers.²⁸ In Spain, 38% of 241 jihadists arrested or killed from 2013 to 2017 held Spanish nationality and 46% Moroccan.²⁹

What about the United States? #

Most lethal jihadist attackers in the US since 9/11 were US citizens, and the government's own wider count of terrorism convictions points the other way. The two figures measure different things.

• New America counts attackers and plotters inside the US. Of 16 lethal jihadist attackers after 9/11, nine were US-born citizens. One was a Saudi officer on a training visa; the rest were immigrants or the children of immigrants.³⁰
• The Justice Department and Homeland Security reported in January 2018 that 402 of 549 people (73%) convicted of international terrorism offences from 2001 to 2016 were foreign-born.³¹ Critics noted that the list included about 90 people arrested abroad and brought to the US, and convictions for wider offences.³²
• The Cato Institute, which favours more immigration, estimates the yearly risk of an American being killed by a foreign-born terrorist at about 1 in 4.5 million, with 98% of those deaths on 11 September 2001.³³

The Washington shooting changed US policy even though no motive has been stated in court (see below). The Mall of America suspect is presumed innocent.

Do studies find that migration causes terrorism? #

Most cross-country studies find no general link between the number of migrants or refugees a rich country takes in and its level of terrorism. Some find narrower links.

Little or no general link:

• A review in the British Journal of Political Science (2022) found little evidence that more migration raises terrorism in Western countries.⁵⁴
• A Journal of Politics study (2022) found no systematic link between refugee inflows and terrorism in host countries, and found refugees were more often targets.⁵⁵
• The ICCT (2025) called radicalised migrants an "infinitesimally small" fraction of asylum applicants, against about 8.5 million first-time applications in its period.⁴⁹⁵⁰

A narrower or conditional link:

• Bove and Böhmelt (2016) found that terrorism can spread through migrants from countries with high terrorism, although overall migrant inflows went with fewer attacks.⁵³
• Dreher, Gassebner and Schaudt (2020) found more foreigners raised the chance of an attack, but no more than the same growth in the native population would, and that exclusionary policies raised the risk.⁵⁶
• Milton, Spencer and Findley (2013) found refugee flows raised the likelihood of transnational attacks in host countries.⁵⁷
• The CTC Sentinel study of Germany found that eight of nine attackers from 2020 to 2025 came through the asylum system.⁵¹
• The ICCT found that long, uncertain asylum procedures increase the risk of radicalisation.⁴⁹

The two kinds of evidence answer different questions. Statistical studies ask whether the size of an inflow predicts terrorism. Case studies ask whether particular asylum routes were exploited or failed. A Danish study found that a large majority of attackers in the decade to 2017 were EU citizens, while also recording returning fighters who travelled on migrant routes in 2015.⁵²

How did Europe change vetting and deportation? #

The European Union. The EU's Screening Regulation applies from 12 June 2026. Everyone who enters irregularly or applies for asylum at the border now goes through identity and security checks against EU databases, with health checks and biometric registration.⁴⁰ The Eurodac database now takes fingerprints from age 6 and facial images, and can flag people with terrorism links.⁴¹

Germany. After Solingen, Germany cut benefits in October 2024 for asylum seekers whose cases belong to another EU state, and banned knives at festivals, markets and on public transport.⁴² It deported 31 Afghan men on a direct flight to Kabul in July 2026, 30 of them convicted of serious crimes.⁴³ Of 471 Islamist "Gefährder" (people police think could commit a serious attack) at the end of 2024, 276 held German or dual citizenship and 195 did not.⁴⁴ The count was 410 on 1 July 2026, down from a peak of 761 in 2018.⁴⁵ The asylum office sent 4,224 possible security leads to federal police in 2025, double the 2,151 of 2024.⁴⁶

France. France keeps a watch list of people reported for radicalisation, the FSPRT. In 2018 about 17% of the 20,459 people on it were foreign nationals. From 2017 to early 2023, 721 radicalised foreigners left France for good, most by forced removal.⁴⁷ France removed 24,985 foreigners in 2025, 15,569 of them by force.⁴⁸ The Mulhouse attack made Algeria's refusal of consular papers a national issue.²²

How did US vetting change after the Washington shooting? #

After the National Guard members were shot in Washington on 26 November 2025, US Citizenship and Immigration Services stopped all asylum decisions, and the State Department paused visas for Afghan passport holders.³⁷ USCIS ordered a re-review of about 233,000 refugees admitted from January 2021 to February 2025, and the refugee ceiling for 2026 was set at 7,500, the lowest ever.³⁸ CBS reported that USCIS had approved 20,354 of 21,201 Afghan asylum claims decided since mid-2021.³⁹ For the election argument over these policies, see the 2026 US midterms.

Questions people ask #

Were the Solingen, Munich and Villach attackers asylum seekers? #

Yes. The Solingen attacker was a Syrian asylum seeker due to be transferred to Bulgaria, and the deadline passed. The Munich attacker was an Afghan whose asylum claim had been refused but who was allowed to stay. The Villach attacker was a Syrian who had been granted asylum in Austria and radicalised online in 2024. All three received life sentences.

What does Europol say about migrants and terrorism? #

Europol says terrorist groups have used migration routes in a few cases, above all the Paris attacks of 2015, but not systematically. It has never published the share of attackers or suspects who were asylum seekers. Where it splits jihadist suspects by citizenship, EU citizens are the larger group.

Was the Berlin Pride attacker in 2026 a migrant? #

No. The man who drove a van into people near Berlin's Pride event on 25 July 2026 was a German citizen born in Germany, according to the German interior minister as reported by AP. One woman was killed. He was shot dead by police the next day.

Why could the Mulhouse attacker not be deported? #

He was an Algerian in irregular status with a removal order and a 2023 conviction for glorifying terrorism. France's interior minister said Algeria had refused ten requests for the consular papers needed to deport him. That claim comes from the French government and has not been independently confirmed.

Is there a link between refugees and terrorism? #

Most statistical studies of rich countries find no general link between the number of refugees taken in and the level of terrorism. Some find narrower links, such as terrorism spreading through migrants from countries in conflict. Case studies show that some attackers did come through the asylum system, and that refused applicants were often not removed.

Were the New Orleans and Boulder attackers immigrants? #

The New Orleans attacker of January 2025 was a US-born citizen and Army veteran. The Boulder attacker of June 2025 was an Egyptian national who had overstayed a tourist visa and had an asylum claim pending. He was given life without parole in state court.

Are most Muslims extremists? #

No. Europol counted 347 jihadist arrests in the whole EU in 2025, in a bloc with millions of Muslim residents. Jihadists treat Muslims who reject them as enemies, and Muslims are among their victims. The attackers on this page were Muslims or converts who became radicalised; they do not speak for Muslims as a whole.

Related guides #

• Immigration Issues: sourced reports on immigration in the US, Somali communities, France and the world.
• Islamist terrorist attacks in Europe: the full list and Europol's yearly counts.
• Islamist terrorism in the US: the US record since 9/11.
• How radicalisation works: online, in prison and in person.
• Countering extremism: what works.
• France's 2027 election and the 2026 US midterms: how immigration and Islamism figure in the campaigns.

Cite as: The Analyst, "Migration and Islamist Terrorism: What the Data Shows", Fighting Islamists, updated 19 October 2026. https://fightingislamists.com/islamist-terrorism-migration.html

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