Swedish police on Sunday arrested two people and detained around 10 people after a violent riot broke out at a protest involving a burning of the Quran, AFP reported.
The protest was organized by Iraqi refugee Salwan Momika, whose previous acts of burning the Quran have sparked outrage across the Middle East.
Sunday's protest was held in a square in the southern city of Malmo, which has a large immigrant population, and according to public broadcaster SVT around 200 people had showed up to watch.
"Some onlookers have shown upset feelings, after the organizer burned writings," police said in a statement.
"The mood was at times heated," the statement said, adding that a "violent riot" occurred at 1:45 p.m. local time (1145 GMT).
According to police, the event had ended after the organizer left but a group of people remained at the scene.
About 10 people were detained for disturbing the public order and another two were arrested, suspected of violent rioting.
Local media reported that some onlookers threw rocks at Momika, and video from the scene showed some trying to break through the cordon before being stopped by police.
In another video a man could be scene trying to stop the police car that transported Momika from the location by getting in front of it, according to the AFP report.
Sweden subsequently raised its terror alert to the second-highest level, saying the country had become a priority target for terrorist groups.
Similar acts of Quran desecration have taken place in Denmark, which recently announced it plans to ban Quran burnings.