Stockholm police called in reinforcements from across Sweden on Friday to quell a possible sixth straight night of riots in the capital's immigrant-dominated suburbs as Britain and the United States warned against travelling to the hotspots.
Nearly a week of nightly riots have put Sweden's reputation as an oasis of peace and harmony at risk.
The unrest has also sparked a debate among Swedes over the integration of immigrants, many of whom arrived under the country's generous asylum policies, and who now make up about 15 percent of the population.
"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 would not disclose how many additional police officers were due to arrive.
But the nightly unrest has prompted Britain's Foreign Office and the US embassy in Stockholm to issue warnings to their nationals, urging them to avoid the affected suburbs.
Firefighters were dispatched to 70 different locations in greater Stockholm overnight, extinguishing torched cars, dumpsters and buildings, including three schools and a police station, the fire department wrote on Twitter.
That was slightly calmer than the previous night, when they handled 90 incidents.
Parents and volunteer organisations who have patrolled the streets in recent nights have helped decrease the intensity of the unrest, Lindgren said.
He said 13 people had been arrested overnight, bringing to 29 the total arrests since the start of the riots on Sunday.
The troubles had begun in the suburb of Husby, where 80 percent of inhabitants are immigrants, triggered by the fatal police shooting of a 69-year-old Husby resident last week after the man wielded a machete in public.
Local activists said the shooting sparked anger among youths who claim to have suffered from police brutality and racism.
One of the rioters in Husby told Swedish Radio that racism was rampant where he lived, and that violence was his only way of being noticed.
"We burned cars, threw rocks at police, at police cars. But it's good, because now people know what Husby is... This is the only way to be heard," said the rioter, identified only by the pseudonym Kim.
In the suburb Rinkeby, six cars parked alongside each other were torched overnight. A police station and several shops in another area Aelvsjoe were set on fire, but the flames were quickly extinguished.
Firefighters said a fire set at a school in another immigrant-heavy suburb, Tensta, was quickly extinguished, as was another at a nursery school in the Kista suburb.
And police in Soedertaelje, a town south of Stockholm, said rioters threw stones at them as they responded to reports of cars set alight.
Flames from another burning vehicle in the suburb of Jordbro spread to a shopping centre, which suffered significant damage before the fire could be put out.
Each of the country's major insurance companies If, Folksam and Trygg-Hansa has received 20 to 30 claims for cars that have been torched, according to Swedish Radio.
The station quoted an If executive as saying her company would end up paying "millions" of kronor (hundreds of thousands of dollars) in compensation.
Stockholm county police chief Mats Loefving said Friday the rioters were local youths with and without criminal records.
In addition, "in the midst of all this there is a small group of professional criminals, who are taking advantage of the situation to commit crimes like this," he told Swedish Radio.
A 25-year-old who grew up in Husby said he didn't think the riots had anything to do with the shooting.
"I'm not saying there are no problems... but people are glorifying this a little bit," said the man, who declined to be named, adding that the rioters were often aged 12 to 17.
"I can imagine they get a big kick out of seeing themselves on TV," he said.
Due to its liberal immigration policy, Sweden has in recent decades become one of Europe's top destinations for immigrants, both in absolute numbers and relative to its size.
But many of those who have arrived struggle to learn the language and find employment, despite numerous government programmes.
Official data shows unemployment was 8.8 percent in Husby in 2012, compared to 3.3 percent in Stockholm as a whole.
Eric Zemmour, a right-wing French commentator known for his controversial views, meanwhile told RTL radio the riots showed that the Swedish "kingdom of social democracy and of political correctness" was little different from countries like Britain and France.