New protests
Media reports spoke of around 50 foreigners, including Germans.
Flemming Steen Munch, a police spokesman, said police were readied for renewed clashes on Saturday night and drafted reinforcements from other districts and borrowed police vans from Sweden.
A new demonstration was planned in the capital at 10 pm (21:00 GMT), activists said. Media reports said protesters were urged via mass cellphone text messages to demonstrate.
A peaceful demonstration was also held on Saturday evening in Copenhagen's multi-ethnic, working class Norrebro district, the focus of recent protests.
Nikolaj Villumsen, a member of the Socialistic Youth Front, told Al Jazeera that he did not support the violence but he believed Denmark needed more youth centres.
"If the politicians don't want to give a new house to the young people then the conflict will go on.
"The Danish government should provide a house for the young people. It will only cost about 12 million Danish krone.
"The government has already spent about 7 million krone in trying to combat the riots."