Member States estimate that there could up to 30,000 ISIL fighters in Iraq and Syria. A significant proportion of them are foreigners, and the majority of the European nationals return home.
As awareness of the risk grows, CTED has been providing Member States with advice and guidance on how to manage the risk posed by foreign terrorist fighters.
For the latest episode of our Lid is On podcast, we asked David Wells, political analysis and research Unit coordinator for CTED, to explain the challenges and potential solutions to the problem.
Music credit: "Fater Lee" by Black Ant.