Islamic State wants to carry out attacks in Germany and the security situation is "very serious", the head of the country's domestic intelligence agency (BfV) told a Sunday newspaper, adding that he knew of no concrete plot to strike.
The militant group released a video on Tuesday suggesting it may carry out further attacks in the West after the Brussels bombings and Paris attacks, naming London, Berlin and Rome as possible targets.
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Hans-Georg Maassen told German newspaper Welt am Sonntag the group wanted to carry out attacks against Germany and German interests, but added, "At the moment we don't have any knowledge of any concrete terrorist attack plans in Germany."
He said Islamic State propaganda was aimed at encouraging supporters to take the initiative to stage attacks in Germany.
Maassen said there were several cases linking Germans returning from Syria to attack plans and warned that the danger posed by militants from Germany remained "virulent".
He said the country had avoided a big attack so far thanks to the successful work of security authorities and luck such as a bomb detonator not working properly on one or two occasions.
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In 2014, a German man described as a radical was charged with planting a pipe bomb -- which never exploded -- at Bonn train station in 2012. In 2006, two suitcase bombs left by Islamist militants on trains in Cologne failed to explode.
Asked how many extremists in Germany were considered highly dangerous, Maassen said there were about 1,100 who were seen as a potential terrorism risk.
Maassen said his agency was aware of about 300 attempts by Salafists and other extremists to recruit refugees.
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"I'm particularly concerned about the many unaccompanied minors -- this group is being deliberately targeted," he said, adding that he saw a "huge radicalisation potential" in these attempts to recruit people.