| IS released the video on Tuesday |
Germans should be prepared for
further attacks carried out by small groups and radicalised "lone
wolves", Interior Minister Thomas de Maiziere has warned.
A video emerged in which he said he was a soldier of so-called Islamic State.
Was it really an IS attack?
Mr de Maiziere said the teenager had been "incited" by IS propaganda but there was no evidence that he was following the militant group's orders.Witnesses said the attacker, Muhammad Riyadh, screamed "Allahu Akbar" (God is great) three times, and IS has claimed the teenager as a follower through its news agency. A hand-painted IS flag was found in his room.