Copenhagen -- Danish Justice Minister Lene Espersen said a recent wave of fires deliberately set in several cities amid a new row over the Mohammed cartoons was "completely unacceptable."

During the past week, cars and trash containers have been set on fire in Copenhagen, and overnight Friday and over the weekend, several other cities including Aarhus also reported burning cars or dumpsters.

A school in a Copenhagen suburb was also set ablaze overnight.

Police said six youths were to appear in court Friday on suspicion of arson and other crimes.

"It is shocking and worrying," Espersen told news agency Ritzu of the blazes, adding that there were "other means" to express discontent than throwing stones at police or emergency services or setting fires.

The authorities blamed mainly juveniles from immigrant families for the attacks, and welcomed efforts by parents and volunteers who have patrolled the streets trying to calm youths.

A year ago, parts of Copenhagen were impacted by rioting when a building that housed an independent youth center was evicted and torn down, triggering massive protests.

Copenhagen mayor Ritt Bjerregaard also slammed the arson attacks, noting fears among inhabitants in affected districts.

Copenhagen University sociologist Rene Karpantschof said the unrest could be linked to growing social and economic inequality. Police had also been given greater leeway to search people, increasing tensions among some groups.

"It is not unreasonable that the unrest is inspired by the actions of the youth center activists, but also by events in France," he said according to Ritzau, referring to events in some Paris suburbs.

Karpantschof did not rule out a link to the recent arrests of three men suspected of plotting to murder a Danish newspaper cartoonist. Two of the men were Tunisian nationals and face deportation.

Kurt Westergaard, 73, who drew the cartoon that depicted Mohammed wearing a bomb as a turban, told public broadcaster DR in an interview late Thursday that he did not regret his work.

"I am too old and stubborn to back down," Westergaard said, saying he had been threatened by "fanatics" while "I only did my job."

He said the cartoon was aimed at illustrating how some groups get "spiritual dynamite" from Islam.

The cartoon was one of 12 published in newspapers that sparked violent protests in 2006 by Muslims around in the world.

Westergaard said his cartoon was made against the backdrop of the Danish context and was "sad" that the cartoon had caused deaths.

Leading Danish newspapers Wednesday republished the cartoon after police said they had uncovered an alleged plot to murder Westergaard.

The publication was said to be a stand for freedom of expression.

DPA with Expatica