According to detectives the attacker was a 27-year-old Syrian man who had been denied asylum in Germany.

Security officials say he detonated the explosive device after he was refused entry into a music festival, being attended by thousands of people, because he didn’t have a ticket.

Joachim Herrmann, Bavaria’s interior minister, said the contents of his backpack had the potential to kill and injure many more victims as they included both explosives and metal parts.

“Due to the situation in Syria, he was not deported. In spite of the rejected application, he was given exceptional leave to remain,” Herrmann said.

The suspect was known to the authorities and had repeatedly received psychiatric treatment, including for attempted suicide.

“We don’t know if this man planned on suicide or if he had the intention of killing others,” Herrmann said.

“My personal view is that I unfortunately think it’s very likely this really was an Islamist suicide attack,” he told German news agency dpa.

“The obvious intention to kill more people indicates an Islamist connection.”

Michael Schrotberger, a spokesman for the prosecutor’s office in Ansbach was more cautious in his remark.

“If there is an Islamist link or not is purely speculation at this point,” he said.

A large-scale operation involving 200 police and 350 rescue workers was launched, and a helicopter brought in.

Witness Thomas Debinski said, “People were definitely panicking. The rumour we were hearing immediately was that there had been a gas explosion.

“But then people came past and said it was a rucksack that had exploded. Someone blew themselves up.

“After what just happened in Munich, it’s very disturbing to think what can happen so close to you in such a small town.”

A police statement stressed that it seems the attacker acted alone as there are no sign of others.

More than 2,000 people have been evacuated from the nearby festival, which has now been cancelled.

Germany has been on high alert following a series of incidents in recent days.