EU threats: Drones, frustrated jihadis, returning fighters

NEWYou can now listen to Fox News articles!

Europe's top law enforcement agency says explosives that mimic those used in Syria and Iraq are a leading threat to the European Union, along with returning fighters and would-be jihadis blocked from traveling to the war zone.

In a report Thursday summarizing trends from 2016 and looking ahead, Europol says Islamic extremists bent on attacking Europe are trending younger and more of them are female than ever before.

Arrests for jihadi activities rose last year for the third year in a row: from 395 in 2014 to 718 in 2016. Nearly a third of those arrested were 25 or younger.

The report says governments are paying close attention to the use of drone explosives by the Islamic State group in Iraq, for fear that homegrown extremists will replicate the weapons.