Police in Stockholm have called in reinforcements amid fears that riots could enter a sixth night. Schools and cars have been set ablaze in the capital's suburbs in five consecutive nights of violence.
Stockholm police said they were calling in officers from around the country to quell further rioting on Friday night.
"We will be getting reinforcements from Gothenburg and Malmoe tonight," police spokesman Kjell Lindgren said, referring to the country's second and third largest cities. He did not reveal how many officers were being sent to the nation's capital.
Eight people were arrested on Friday, mostly in their early twenties, bringing the total from the week to 29. While Thursday was slightly calmer than the previous four evenings, at least 30 cars and several buildings were set alight including a police station and a school in the northern suburb of Kista.
The previous night police were called out to deal with some 90 incidents.
Police say the attacks don't appear to be coordinated.
The riots, the worst to hit Sweden in years, have shaken a nation famed for its openness, tolerance and model welfare state. Critics of the Swedish government say they have exposed a widening gap between the rich and poor - mostly young people with immigrant backgrounds. Widening youth unemployment has also been blamed.
Although rioting began on Sunday, tensions have been high in Stockholm since police shot dead a 69-year man in the suburb of Husby earlier this month. Police said the man, reported to be a Portuguese immigrant, was wielding a knife. Immigrant groups, however, have accused the police of heavy handedness. Unemployment is high in Husby, where 80 percent of the suburbs 12,000 residents are immigrants.
Britain and the US have responded to the surge in violence by urging nationals against travel to the affected suburbs.
ccp/kms (AFP, Reuters, dpa)