A Syrian refugee who had been denied asylum in Germany a year ago died when a bomb he was carrying exploded outside a music festival in Ansbach, Germany.

Twelve people were wounded in the attack on Sunday night, three of them seriously.

The 27-year-old, who arrived in Germany two years ago, was denied asylum last year but was allowed to remain in Germany because of the ongoing conflict in Syria, Bavarian Interior Minister Joachim Herrmann said early on Monday.

The man had tried to kill himself on two prior occasions and had been treated at a psychiatric clinic, the minister said. The suspect was known to police.

It was unclear if he had planned to commit suicide or "take others with him into death", the Nordbayern.de website reported.

The bombing was being treated as attempted murder by the Bavarian state prosecutor, but authorities were still investigating whether the crime was an act of terrorism.

"We can't rule it out," Herrmann told reporters in Ansbach.

Herrmann said early on the man, carrying a backpack, had apparently been denied entry to the Ansbach Open music festival shortly before the explosion.

More than 2000 people were evacuated from the festival after the explosion, police said.

The open air concert came to an immediate halt after the bombing and panic ensued in the city centre.

(Source: Yahoo news)