A man has blown himself up the town of Ansbach, southern Germany, injuring 12 people, German media report.

Of these, three have been seriously wounded.

The attacker has triggered the explosives outside a wine bar, during a music festival, after being denied entry.

He was a Syrian national whose application had been rejected, Der Spiegel quotes Bavaria's Interior Minister Joachim Herrmann as saying.

He reportedly made suicide attempts two times after his request was turned down.

According to Herrmann, the man was allowed to stay despite the refusal due to the situation in Syria.

It is not clear as of the moment whether the incident was a terrorist attack. Munich police describe it as a "deliberate explosion", but did not immediately find a link with the Islamic State (IS) group.

This is the fourth attack in Germany in just a week. On Friday, ten people lost their lives in a shooting in a Munich shopping center. Later on, an asylum seeker from Syria was taken into custody after reportedly killing a woman with a machete. However, police have no evidence of the latter two being terror-related. 

Last Tuesday, the IS group claimed responsibility for an axe attack committed by an Afghan national.