ISIS in the West

The Western Militant Flow to Syria and Iraq
by Peter Bergen, David Sterman, Alyssa Sims, and Albert Ford


hree coordinated terrorist bombings killed 31 people and wounded around 300 more in Brussels on March 22, 2016. Four days prior to the attacks, Belgian police captured Salah Abdeslam, the only surviving attacker from the Nov. 13, 2015 Paris attacks that killed 130 people. Abdeslam told Belgian authorities after his capture that he was “ready to restart something from Brussels.” The links between the Paris and Brussels terrorists raise three important questions: Who are the Western “foreign fighters” who have left for Syria? How deep do their networks run? What threat they pose when they return to the West?

New America has examined 604 militants from 26 Western countries who, according to credible news sources, left their home countries to fight with ISIS or other Sunni jihadist groups in Syria or Iraq. This report is an updated version of our original November 2015 report “ISIS in the West.”

Key Findings

The Status of Western Foreign Fighters

At large (237 of 604)
Dead (239 of 604)
Returned and outside custody
(20 of 604)
In custody (108 of 604)

The Threat to the United States


he threat to the United States from returning fighters is low and will likely be manageable. So far, no returnee from the Syrian conflict has conducted an attack in the United States. However, the United States will have to remain aware of the threat from European returnees -- many of whom come from countries that are part of the United States’ visa waiver program. ISIS-inspired violence will pose the most likely threat to the United States.

Five years into the Syrian civil war, there is little evidence that American militants pose a significant threat of returning to conduct attacks inside the United States. Of the 94 cases of Americans that we found who have been drawn to the Syrian war, only 27 actually reached Syria. For 49 of the 94 American cases, their attempts to reach Syria did not succeed. In 18 cases the criminal activity consisted of providing support to other militants fighting in Syria or those militants attempting to fight there.

The Status of American Foreign Fighters

At large (8 of 94)
Dead (12 of 94)
Returned and in custody
(6 of 94)
In custody abroad
(1 of 94)
Arrested before reaching Syria
(67 of 94)

The Threat to the West Broadly


he threat facing Europe is severe. Well-developed jihadist networks in Europe -- particularly in France and Belgium -- have demonstrated their capability to conduct deadly attacks. This is particularly true of the Brussels neighborhood of Molenbeek, where, according to New America research, 13 of the 31 people associated with November’s Paris attacks are from. The threat is also driven by the large number of Europeans who have traveled to fight in Syria and the existence of more developed jihadist networks in Europe.

There are an estimated 6,900 Western fighters who have gone to fight in Syria. Several nations including France, Belgium, and Germany are reporting strains on their ability to effectively monitor returnees. According to officials interviewed by the New York Times, each French individual placed under surveillance requires 25 agents to maintain round the clock monitoring.

Western European countries face a greater threat than the United States because militants can draw upon more established jihadist networks that can give rise to more sophisticated and deadly attacks. The Paris attacks succeeded because the 10 key perpetrators relied on a network of 21 militants that New America has identified who aided the attackers both in Belgium and France. In Belgium, the Sharia4Belgium radical Salafist group actively encouraged and aided members’ travel to Syria. A total of 46 group members were eventually tried in Antwerp and convicted in February 2015.

Read the Report