STOCKHOLM: At least nine cars were torched and two schools and a police station were set ablaze as riots swept through Stockholm's immigrant-dominated suburbs early Friday for the fifth straight night, police and firefighters said.

The riots, which have shattered Sweden's image abroad as a peaceful and egalitarian nation, have sparked a debate about the assimilation of immigrants, who make up about 15 per cent of the population.

Many of the immigrants who have arrived due to the country's generous refugee policy struggle to learn the language and find employment, despite numerous government programs.

Early Friday, police told Swedish news agency TT eight people had been arrested so far for the night's rioting, but no injuries were reported.

In Rinkeby, one of the city's immigrant-dominated areas, firefighters rushed to put out flames that engulfed six cars parked alongside each other.

Five cars were totally gutted, and one sustained more moderate damage, according to an AFP photographer on the scene.

Three more cars were torched in the Norsborg suburb, and a police station in Aelvsjoe was set on fire but quickly extinguished, police said.

Firefighters meanwhile said a school in another immigrant-heavy suburb, Tensta, was set ablaze but quickly extinguished, and a nursery school in the Kista suburb was also on fire.

And police in Soedertaelje, a town south of Stockholm, said rioters threw stones at them as they responded to reports of cars set alight.

The previous night, the fire brigade had been called to some 90 different blazes, most of them caused by rioters.

“We are gradually becoming more like other countries,” said Aje Carlbom, a social anthropologist at Malmoe University.

The troubles, which began Sunday in the Husby suburb, are believed to have been triggered by the fatal police shooting of a 69-year-old Husby resident last week after the man wielded a machete in public.

The man had fled to his apartment, where police have said they tried to mediate but ended up shooting him dead in what they claimed was self-defence.

Local activists said the shooting sparked anger among youths who claim to have suffered from police brutality. During the first night of rioting, they said police had called them “tramps, monkeys and negroes”.

Police meanwhile downplayed the scale of the events.

“Every injured person is a tragedy, every torched car is a failure for society...but Stockholm is not burning. Let's have a level-headed view of the situation,” Ulf Johansson, deputy police chief for Stockholm county, said Thursday.

Residents of areas largely populated by immigrants are suffering from segregation, anthropologist Carlbom told AFP.

“Living as a young person in these segregated areas can be very hard in many ways. You have virtually no contact with other Swedes and a lot of times I don't think you have a good understanding of Swedish society,” he said.

For example, some 80 per cent of the 12,000 residents in Husby are immigrants.

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.

In the past decade it has welcomed hundreds of thousands of immigrants from Iraq, Afghanistan, Syria, Somalia and the Balkans, among others.

This is not the first time the Scandinavian country has seen riots among immigrants. In 2010, up to 100 youths threw bricks, set fires and attacked the local police station in the immigrant-dominated suburb of Rinkeby for two nights.

And in 2008, hundreds of youths rioted against police in the southern Swedish town of Malmoe, sparked by the closure of an Islamic cultural centre in the suburb of Rosengaard that housed a mosque.

Integration Minister Erik Ullenhag attributed the violence to high unemployment and social exclusion in Sweden's immigrant-dominated areas.

“We know that there is discrimination in these areas, and these events don't improve the image of these areas, where there is a lot of positive stuff going on but which is totally eclipsed right now,” he told TT.

In Husby, overall unemployment was 8.8 per cent in 2012, compared to 3.3 per cent in Stockholm as a whole, according to official data.

And a total of 12 percent in Husby received social benefits last year, compared to 3.6 per cent in Stockholm as a whole.

The riots have received international media attention, with some comparisons being drawn to similar problems assimilating immigrants in other European countries such as Britain and France.