"During the summer of 2015, the so-called Islamic State is still being a dangerously tempting destination for young Islamists from Germany," Hans-Georg Maassen said, quoted by the media outlet.
Maassen stressed that many young Germans who left for Syria appeared to not understand that ISIL would force them to carry out suicide attacks.
According to Spiegel, one third of the jihadists joining ISIL in Syria or Iraq have returned to Germany. Around one hundred militants from Germany have died in the conflict area, a death toll twice that of the previous year.
ISIL has seized large territories in Iraq and Syria. The group, notorious for their multiple and ongoing human rights atrocities, uses social media networks to recruit new members. Some 20,000 foreign militants have traveled to Syria and Iraq to join ISIL, according to US intelligence.