BERLIN - Three people were seriously injured on Friday after a knife attack in Germany's southwestern city of Ravensburg.

A young man stabbed three people with a butcher knife in the city center of Marienplatz, and one of the wounded was in life-threatening conditions, according to local police.

Patrolling police rushed to the scene and arrested the suspect.

The local police later released a statement on its website saying the suspect was a 19-year-old asylum-seeker from Afghanistan, and he mounted the attack "for unknown reasons."

So far there is no evidence of a terrorist attack and the investigation is going on, the statement said.