Forty three people have been arrested after a sixth consecutive night of violence in immigrant neighbourhoods in Danish cities, police officials say.

On Saturday police arrested groups of youths in Copenhagen, Aarhus, Ringsted, Slagelse and other cities after they set fire to schools, cars and rubbish bins and threw rocks at frefighters.

Michael Hoejer, the deputy national police commissioner, said: "The bad [news] is that there's been a lot of vandalism; they've set fire to cars, garbage containers and in some cases buildings.

"The good news is that we've made a lot of arrests," he said.

The spate of vandalism started last weekend and is believed to have intensified after Danish newspapers reproduced a cartoon of the Prophet Muhammad on Wednesday.

Hoejer said most of those arrested and later released were teenagers, but he declined to say how many.

Across the country more than 30 cars and 50 containers have been torched, and buildings such as schools and garages have also been targeted.

Hoejer rebuffed earlier police reports that the situation in Copenhagen, where police made 11 arrests, seemed to be calming.

"On Thursday the Copenhagen situation showed signs of calming, but it got worse last night again," he said.

Cartoon reprint

Police say they are not sure what has triggered the violence but observers say immigrant youths are protesting against perceived police harassment.

The situation may have been aggravated after Danish newspapers reprinted a cartoon that sparked massive protests in Muslim countries two years ago.

The reprinting of the cartoons, seen as a gesture of solidarity after police revealed an alleged plot to kill the cartoonist, also sparked protests in Pakistan and Bangladesh.

The reproduction of the cartoon has sparked protests and anger in many Muslim countries because Islamic law generally opposes any depiction of the Prophet, even favourable, for fear it could lead to idolatry.

PHOTO CAPTION

Firemen put out a burning car in Copenhagen, Denmark.

Al-Jazeera