The rioting - set off earlier this month by the police shooting of a 69-year-old man - continued for a sixth night in mainly poor immigrant areas in Stockholm.
In a country with a reputation for openness, tolerance and a model welfare state, the rioting has exposed a fault-line between a well-off majority and a minority - often young people with immigrant backgrounds - who are poorly educated, cannot find work and feel pushed to the edge of society.
Two cars were torched in Stockholm but the city appeared to have had its calmest night since the trouble began.
"It is a bit calmer. Of course, there are still fires," said Towe Hagg, a police spokeswoman in Stockholm.
But in Orebro, a town in central Sweden, some 25 masked youths set fire to three cars, a school and tried to torch a police station, police said. An old empty building was set alight in the town of Sodertalje, less than an hour's drive from the capital.
Pupils at a primary school in the Stockholm suburb of Kista - an information-technology hub that is home to the likes of telecoms equipment maker Ericsson and the Swedish office of Microsoft - arrived on Friday to find the inside of the small red wooden building had been burned out.
"In the short run, the acute thing is to ensure that these neighborhoods get back to normal everyday life," Erik Ullenhag, Sweden's integration minister, told Reuters. "In the long run we need to create positive spirals in these neighborhoods."
The police said they had called in backup from the cities of Malmo and Gothenburg. Prime Minister Fredrik Reinfeldt held an emergency meeting on Friday to discuss the crisis.
The spree of destruction has seen masked youths vandalise schools, libraries and police stations, setting cars alight and hurling stones at police and firefighters.
It was sparked by the fatal police shooting earlier this month of a 69-year man, reported by local media to be a Portuguese immigrant and suspected of wielding a large knife, in the Stockholm suburb of Husby.
The scale of riots pales to the disturbances seen in London and Paris in recent years and there have been almost no injuries. Much of the capital has gone about business as normal.
But the violence - with more than 100 cars set ablaze this week - has shocked a nation that has long taken pride in its generous social safety net.
Youth unemployment is especially high in neighborhoods such as the ones where the riots have taken place, home to asylum seekers from Iraq to Somalia, Afghanistan and Latin America.
About 15 percent of Sweden's population is foreign born. While many are from neighbouring Nordic countries, others are drawn by the country's policy of welcoming asylum seekers from war-torn countries.
Kicki Haak, head of the small Montessori school that was set alight in Kista on Thursday night, said she did not know if it would be able to reopen. The 94 students will move into improvised classrooms in nearby office buildings on Monday.
"Five nights in a row - it's incomprehensible," said Faisal Lugh, whose two children are pupils at the school.
"My children asked about the things they had there: 'How about my books? My rain jacket? My pictures? Are they all gone?'" said Lugh, who works for an unemployment office and often helps new immigrants find jobs.
There are signs that residents in the affected areas are getting fed up with the violence. Many community leaders, dressed in fluorescent jackets, have taken to the streets to try to calm things down.
"When will it stop?" said Maryam Rahimi, who works at a school in Husby that was vandalised.
Risto Kajanto, brother-in-law of the man who was shot dead, told Swedish tabloid Aftonbladet he condemned the violence.
"I want to say to all those who are burning cars that it is totally wrong to react that way," he said.
One recent government study showed up to a third of young people aged 16 to 29 in some of the most deprived areas of Sweden's big cities neither study nor have a job.
The gap between rich and poor in Sweden is growing faster than in any other major nation, according to the Organisation for Economic Cooperation and Development, although absolute poverty remains uncommon.