Hans-Georg Maassen said the terrorist attacks in Paris last November had shown that Islamic State was deliberately planting terrorists among the refugees flowing into Europe.

“Then we have repeatedly seen that terrorists … have slipped in camouflaged or disguised as refugees. This is a fact that the security agencies are facing,” Maassen told ZDF television.

“We are trying to recognize and identify whether there are still more IS fighters or terrorists from IS that have slipped in,” he added.

The Berliner Zeitung newspaper cited Maassen on Friday as saying that the BfV had received more than 100 tip-offs that there were Islamic State fighters among the refugees currently staying in Germany.