Violence continued in the Uppsala suburbs of Gottsunda, Valsätra and Eriksberg as at least eight cars were destroyed in arson attacks.
A police car was subjected to a shower of stones in Gottsunda as the unit was sent to investigate reports of vandalism by youth gangs.
At around 11pm further reports of burning cars were called in by concerned residents in Gottsunda and Valsätra, who have had to sustain continued unrest since the troubles broke out two weeks ago.
"It started on August 28th when the police were called to Gottsunda to investigate a car fire, and were then met with stone-throwing youths. It has since gone in waves, escalated, and spread to other neighbourhoods," Christer Nordström at Uppsala police told the news website Svd.se.
In Södertälje, south of Stockholm, there were reports of serious damage to at least seven cars. Police suspect arson.
The unrest was not however limited to Sweden's east coast with further reports of arson at several locations in western Sweden.
In the Bergsjön area of Gothenburg flammable liquid was sprayed on a tram and set alight. The fire however extinguished itself and the tram was able to continue its journey.
In Kungälv, north of the city, a car was set alight at a parking lot at around 10pm which then spread to a further three vehicles. A bus was also attacked by stone-throwing youths and a fire started outside a local school.
The town of Falkenberg was also the scene of arson attacks, as was the Gothenburg suburb of Hammarkullen.
Christer Nordström reported that many of the members of the public calling the emergency services expressed dismay at the developments in their neighbourhoods.
"That which is very serious is that we have noticed how racist tendencies are starting to grow. This prompts some very strong emotions, even if the majority of those that call are level-headed people," he said to Svd.se.
Police in Södertälje meanwhile played down the recent spate of vandalism and unrest.
"It has been like a normal Friday evening," Mikael Törnblom at Södertörn police told the website.