BERLIN (Reuters) - A Syrian man who injured 15 people when he blew himself up in southern Germany - an attack claimed by Islamic State - called in a video for further attacks, U.S. monitoring group SITE reported, citing Islamic State's Amaq news agency.

The attack that took place on Sunday outside a music festival in Ansbach, a town of 40,000 people southwest of Nuremberg, was the fourth act of violence by men of Middle Eastern or Asian origin against German civilians in a week.

Bavarian Interior Minister Joachim Herrmann said on Monday that a video had been found on the bomber's mobile phone in which he pledged allegiance to Islamic State.

SITE quoted the man in the video saying he was on a "martyrdom-seeking operation" in Ansbach, and calling for more attacks.

He said the attack in Ansbach was in response to "crimes committed by the Coalition in collaboration with Germany by bombing and killing men, women, and children".

In December the German parliament approved plans to join the military campaign against Islamic State in Syria in a mission that includes sending reconnaissance jets, a frigate, refuelling aircraft and military personnel. But Germany has not joined countries like Britain, France, the United States and Russia in conducting airstrikes.

(Reporting by Michelle Martin Editing by Jeremy Gaunt)