HAMBURG SUPERMART KNIFE ATTACK LEAVES ONE DEAD,MOTIVE UNCLEAR SAYS POLICE

One person has been killed and four others injured in a knife attack in a supermarket in the northern German city of Hamburg, the city's police said.

The assailant entered the supermarket in the Barmbek district on Friday afternoon and stabbed one person, who died at the scene, police said.

As he fled, he injured another four people.

He was overwhelmed by passers-by and slightly injured in the process, police said.

Officers then arrested the man.

There was no immediate indication of any political or religious motive for the attack.

Police said they did not yet have any information on the assailant's motive, but there was no indication there were any further attackers.

"It was definitely a lone attacker," Hamburg police tweeted.

Police have been on high alert in Germany since a spate of attacks on civilians last year, including a December attack on a Berlin Christmas market , when a hijacked truck ploughed into the crowds, killing 12 and injuring many more.

Security has been a campaign issue ahead of September 24 parliamentary elections, in which Chancellor Angela Merkel is expected to win a fourth term in office.

Newspaper Bild showed a picture of the alleged Hamburg attacker sitting in the back of a police car, his face concealed with a bloodied shroud.

A video on its website showed a helicopter outside the supermarket with armed police in body armour patrolling the neighbourhood.