An Islamic State fighter carried out the suicide bombing that injured 15 people outside a music festival in German city of Ansbach, the jihadist group claimed on Monday.
"The individual who carried out the martyrdom operation in Ansbach in Germany was a soldier of IS who executed the operation in response to calls to target nations in the coalition fighting the Islamic state," IS's Amaq news agency said, citing an IS source.
Amaq issued the claim of responsibility in Arabic, English and German.
The suicide bomber, Mohammed Daleel, was a 27-year-old Syrian refugee who was set to be deported to Bulgaria after his asylum request was turned down.
Earlier in the day, Bavarian Interior Minister Joachim Herrmann said that the Syrian had pledged allegiance to Islamic State on a video found on his mobile phone,
"I think that after this video there's no doubt that the attack was a terrorist attack with an Islamist background," Herrmann told reporters.
The man threatened a "revenge attack" on Germans in the video, he said.
The Ansbach festival was cancelled after the 27-year-old detonated an explosives-packed rucksack outside a wine bar on Sunday and 2,000 people were sent home.
Daleel had previously had twice attempted suicide and had received treatment in psychiatric unit.