A failed Syrian asylum seeker who blew himself up outside a German music festival had made a video pledging allegiance to the Islamic State terror group. This was the second attack claimed by the IS in Germany in a week.

The 27-year-old assailant wounded 15 people, four of them seriously, near a cafe in the southern city of Ansbach on Sunday night, when he set off a bomb in his rucksack, killing himself.

Bavarian state interior minister Joachim Herrmann told reporters that a video made by the assailant was found on his mobile phone in which he threatened an attack.

Germany is reeling under the IS claimed attacks after nine people were killed in a shopping centre shooting spree in Munich on Friday and five people were wounded in an axe attack on a train in Wuerzburg on July 18.