Bands of youths set fire to cars and trash bins overnight in a fourth consecutive night of vandalism mostly in immigrant neighborhoods of the Danish capital, police said.
Seventeen people were arrested, Copenhagen Police spokesman Flemming Steen Munch said, adding police were not sure what sparked the violence.
Some observers said immigrant youths were protesting against perceived police harassment and suggested the reprinting of a cartoon of the Prophet Muhammad in Danish newspapers Wednesday, may have aggravated the situation.
More than a dozen Danish newspapers reprinted one of the cartoons on Wednesday in a gesture of solidarity after police revealed an alleged plot to kill the creator of the caricature.
Munch said he did not know whether the reprinting of the cartoon had any part in the violence.
“We see different reasons for the rioting,” Munch said. “We do not know why exactly. It can be because of boredom, it can be because police in recent weeks have stepped up its search for knives, it can be other things too.”