Since declaring its so-called “caliphate” in 2014, the Islamic State of Iraq and Syria (ISIS) has exploited European travel laws, organized teams of returning European foreign fighters, and radicalized individuals already in Europe to conduct multi-operative attacks. This capability limits law enforcement’s ability to detect and interdict attacks such as in Paris last November and in Brussels in March.
- In 2013-15, Abdelhamid Abaaoud, a key facilitator in the Paris attacks, moved freely between Syria and Europe, evading border checkpoints in Turkey. In December 2015, Salah Abdeslam, the last surviving Paris attacker, traveled to Belgium without detection and planned additional operations—including the attacks in Brussels—from Molenbeek, a Brussels suburb.
- According to Belgian police, a hybrid coalition of returning foreign fighters from various terrorist groups in the Middle East, including ISIS, as well as extremists radicalized in their own countries, has become rooted in Europe. For example, Abaaoud received training and guidance from ISIS in Syria and after returning to Europe, he identified, recruited, and trained other individuals to carry out the attacks in Paris.
- The attacks in Brussels and Paris demonstrate ISIS’s ability to leverage operatives familiar with target locations. These individuals are embedded within local neighborhoods and can evade law enforcement detection during an operation’s planning phase. For example, ISIS operatives received shelter, supplies, and financing from local sympathizers in Molenbeek prior to the attacks in March at Brussels International Airport and at a Brussels metro station.