In yet another incident of violence in Germany, A Syrian migrant set off an explosion at a bar in southern Germany that killed himself and wounded a dozen others.
It was the third attack to hit Bavaria in a week.
The 27-year-old, who had spent a stint in a psychiatric facility, had intended to target a music festival in the city of Ansbach but was turned away because he did not have a ticket.
"Unfortunately, this is a terrible new attack which will surely increase people's anxiety," regional interior minister Joachim Herrmann said, adding that investigators "have not ruled out" he had an Islamist motive.
Hermann said he was worried "the right to asylum would be undermined" by the events of the past week, which has seen attacks on a train and shopping mall in the southern German state.
Ansbach police said in a statement that just after 10 p.m. Sunday they were alerted to an explosion in the city center. The perpetrator was killed in the explosion, police said in a statement, and a spokeswoman said 12 people were wounded, three of them seriously.
The website for a group of local newspapers, nordbayern.de, reported that none of the injured were in life-threatening condition.
Ansbach deputy police chief Roman Fertinger said there were "indications" pieces of metal had been added to the explosive device.
Herrmann said the attacker, who came to Germany two years ago but had his asylum claim rejected after a year, had tried to kill himself twice in the past and had spent time in a psychiatric clinic.
Europe has been on edge for months after a string of deadly attacks claimed by the Islamic State jihadist group, including bombings in Brussels and carnage at Bastille Day celebrations in the southern French city of Nice.
In Bavaria, which has been a gateway for thousands of Syrian refugees, nine died in a shooting rampage in Munich on Friday and several people were wounded in an axe attack on a train near Wuerzburg.
In another case on Sunday, a woman died and two other people were injured when a machete wielding Syrian asylum-seeker attacked them in the town of Reutlingen, near Stuttgart.
Police said the attacker had been arrested and there was no indication that it was terrorist attack.
Germany, and Bavaria in particular, are on edge after a deadly rampage at a Munich mall on Friday in which nine people were killed and an axe attack on a train near Wuerzburg last Monday in which five people were wounded.
Police released more details of Munich attacker David Ali Sonboly yesterday, saying the 18-year-old was depressed and had spent two months in a psychiatric unit last year.
The teen was obsessed with mass killings and spent a year preparing for the gun attack that killed nine people, most of them foreigners.
At least 35 people were also wounded during Sonboly's shooting spree, which began at a McDonald's branch and ended with him turning his 9mm Glock pistol on himself.
Investigators have ruled out any link with the jihadists, though he appears to have planned the assault with chilling precision.
(With inputs from agencies)