Germany has been hit by wave of often-violent attacks by so-called scary clowns in recent weeks with authorities telling dpa on Wednesday they had reports of about 370 incidents.

The incidents range from sightings of people dressed in clown outfits to clowns with horror masks frightening passersby to attempted and actual attacks on people with knives or other weapons, including baseball bats and chain saws, police and court authorities said.

In one recent incident, a person wearing a scary clown mask and wielding a knife threatened a group of terrified passengers on a train in the western German state of Saarland before being taken into custody by police.

The largest number of creepy clown attacks has been reported in the western German cities such as Duisburg, Cologne and Aachen where people have apparently picked up on the craze, which was originally promoted over social media in the United States.

In another twist in the series of incidents, a 16-year-old boy with clown mask had to undergo an emergency operation on Monday in Berlin after he was stabbed by a 14-year-old he had attempted frighten.

While police have warned that the number of attacks could increase in the run-up to Halloween at the end of the month, circus operators and clowns themselves have expressed concerns about the damage the attacks are causing to the traditional fun-loving image of clowns.