The Islamic State is infiltrating terrorists into Europe “disguised as refugees ”, the head of Germany’s domestic security service has said.
The warning comes after an Algerian man was arrested at a refugee shelter on Thursday on suspicion of planning a terror attack in Berlin.
“We have seen repeatedly that terrorists are being smuggled in disguised or camouflaged as refugees,” Hans-Georg Maassen, the head of the Office for the Protection of the Constitution (BfV), said.
German authorities have so far tried to play down the possibility that Islamic State of Iraq and the Levant (Isil) extremists have entered the country among the 1.1m asylum-seekers who arrived last year.
But in the wake of the latest arrest Mr Maassen said it was a “reality that the security agencies have to face”.
It was already clear from last November’s attacks in Paris that “Isil consciously infiltrates terrorists among the refugees,” he told Germany’s ZDF television.
At least one of the Paris attackers is believed to have entered Europe posing as a refugee.
An Algerian asylum-seeker was among three people arrested on Thursday over an alleged planned attack in the heart of Berlin.
The 35-year-old man, who has not been named, was staying at a refugee shelter in Attendorn, a small town some 50 miles from Cologne, together with his wife and two small children.
His wife is also believed to be among those being held. A third suspect, another Algerian man, was arrested in a separate raid in Berlin.
More details have begun to emerge over the alleged terror plot.
Security services intercepted phone calls between the suspects in which they discussed possible targets in Berlin, according to German press reports.
Targets that were named included Checkpoint Charlie, the former Cold War crossing point between East and West Berlin that is now a tourist site, and Alexanderplatz, a major shopping area.
Mr Maassen said there was “concrete evidence there are people planning terror attacks in Germany”, but stressed there was “no indication of an imminent attack” before the police raids.
Questions will be asked over how the main suspect was able to enter Germany posing as a refugee.
It is understood he was wanted in his native Algeria for links to Isil, and trained with the jihadist group in Syria.
Both he and the man arrested in Berlin are believed to have entered Germany under false identities.
Two other suspects have been questioned in connection with the case but so far have not been arrested, police say.
The BfV has received more than 100 tip-offs aboue alleged terrorists hiding among asylum-seekers, but many turned out ot be unfounded on investigation, Mr Maassen said.