A teenager’s attempt to frighten a group of young people by wearing a clown mask and brandishing a hammer on a Berlin street has turned out very badly, according to German police.

Berlin police said on Tuesday that a 14-year-old responded by pulling a knife and stabbing the clown, only to find that the clown was a 16-year-old acquaintance.

He provided first aid until emergency medical help could arrive. The older teenager was taken to a hospital. The 14-year-old was released to his parents.

Another clown incident was reported by Austrian police, the APA news agency reported. Police said a 19-year-old was injured after being chased by two people dressed as clowns who jumped from bushes in Schwaz, a town in western Austria. A third clown joined the chase and attacked the man with a baseball bat.

News media in Europe and the US have reported a rash of sightings – some confirmed, some not – of people dressed as clowns and acting in a disturbing manner.

Berlin police warned that scaring another person, especially with threats of violence, could constitute a criminal offence and result in a hefty fine and compensation claims from the victims.