Germany's domestic spy chief says at least 170 Islamic extremists have traveled to Syria from Germany and some are thought to be actively participating in the fighting.
Hans-Georg Maassen told Deutschlandfunk radio in an interview broadcast Sunday that about 50 extremists have gone from Germany to Syria in recent months alone.
The head of the Federal Office for the Protection of the Constitution says he is concerned that some of these extremists may return to Germany with plans for terror attacks.
German security agencies claim to have foiled a number of planned attacks by Islamic extremists in recent years.
