Several people have been killed and others injured in a knife attack in the southern city of Wuerzburg on Friday, various foreign news agencies reported.

"The attacker was overpowered after the police used firearms. There are several injured as well as fatalities," said German police on Twitter.

It was unclear how many people were killed or injured.

Police spokeswoman Kerstin Kunick said officers were alerted around 5 pm to a knife attack on Barbarossa Square in the center of the city.

Police said on Twitter that there is no danger to the population.