Germany's domestic intelligence agency says it has recorded hundreds of attempts by radical Islamists to recruit immigrants hosted in the country's refugee centres.
"We know of more than 340 incidences," the head of Germany's Federal Office for the Protection of the Constitution, Hans-Georg Maassen, told dpa. "But these are only the cases known to us. Presumably there are even more."
Workers at German refugee centres have already been made aware of the situation, Maassen said.
"It worries us that Salafists and other Islamists are promoting their cause in asylum centres," Maassen said, referring to an ultra-conservative reform movement within Sunni Islam.
"We know that there are very many young men of the Sunni denomination among asylum seekers. These often come from a conservative Islamic background and want to go to an Arabic-speaking mosque every Friday," the intelligence agency chief said, noting that there were also numerous radical Salafist mosques in Germany.
"Arabic-speaking mosques in Germany are not regulated. From the perspective of the state, there is very little we can influence," Maassen said.
Maassen said that Islamist-motivated attacks had also taken place before a recent spate of violence in the past month in Germany, and that a policeman in the city of Hanover as well as a Sikh temple in Essen had also been targeted.
"The lesson to learn from this is that we should not concentrate only on Islamic State, which may be sending terrorist units to Europe, as with Paris or Brussels," Maassen said. "Instead it could be that individuals that are radicalized on their own or are given orders."