Police in Danish capital city of Copenhagen arrested on Thursday 28 people while investigating the violent demonstrations that took place on Saturday night, local media reported.

The police said the action was part of efforts to locate the individuals involved in the riots, during which police officers were attacked by mobs who threw stones, bottles, fireworks and Molotov cocktails to them, according to the English newspaper The Copenhagen Post.

The police raided a number of addresses after receiving tip-offs, Poul Kjeldsen, a police inspector with the City Police, was cited as saying. He said further investigation into the incident is under way.

Later in the day, 13 of the 28 arrested have been released by the police, and two of them have been charged with vandalism and disturbing the peace, according to the paper.

The arrests are in addition to the three that were made in the early hours of Sunday.

The riots broke out after a Reclaim The Streets demonstration in Copenhagen's Norrebro district turned violent with several financial institutions and estate agents being vandalised. About 200 people took part in the demonstration.