At least one person has been injured after a gunman opened fire in a supermarket in Germany, according to reports.

The incident took place in the Gröpelingen area, in the city of Bremen, on 2 November.

Witnesses said they heard an argument, before some shots were fired, according to Focus Online.

"They shouted at each other," a woman said, but she could not elaborate on the reasons for the argument.

The victim is thought to be seriously hurt, the police said in a statement quoted by Reuters. They are hunting for the gunman, who fled the scene.

"The background to this is not clear," said the police, adding there was no immediate danger to the public.

Several relatives of the victim are with the man, newspaper Bild reported. They broke down in tears and were taken care of by the police.