The police operation targeted a Hells Angels chapter in Gunnilse in Gothenburg and several people were detained during the course of the raid.

“We were very happy with the outcome,” said police spokesperson Stefan Gustafsson to news agency TT.

The raid was part of an ongoing investigation into allegations of assault, robbery and aggravated weapons offences, and was preceded by surveillance.

Västra Götaland police were joined by officers from the National Criminal Investigation Department and hit the club premises at around 6pm on Wednesday and continued all evening. A forensic examination and thorough search of the premises was conducted later.

When the officers forced their way into the premises they found around 20 people present, of whom around a dozen were taken into custody.

“We didn’t ring on the door first,” Gustafsson said.

The arrested have been identified and were interviewed during the course of the evening and the prosecutor will later decide whether to keep them in custody for further investigation. Several were already wanted in connection with other ongoing investigations.

Elsewhere, Gothenburg municipality voted on Wednesday to call on restaurant and bar owners to bar anyone bearing a biker club logo from entry.

The proposal was presented in the autumn and the ban was voted through by the municipal executive board on Wednesday, the local Göteborgs-Posten daily reports.

Eskilstuna municipality took a similar decision last year but the ban was ruled unconstitutional by Södermanland Administrative Court in March 2010. The court ruled that that ban was in breach of legislation guaranteeing freedom of expression.

But Gothenburg municipality have decided to push ahead with the ban regardless.

“We don’t know if this part of our licensing guidelines conforms to the law and if it can be applied in bars and restaurants, but we see this as a show of support for restaurateurs and want to try it out,” municipal councillor Dario Espiga told the newspaper.

The three main criminal motorcycle gangs operating in Sweden are the well-established Hells Angels and Bandidos and the Outlaws, who are relatively new on the scene.

The groups themselves habitually argue that while individual members may commit crimes, the clubs themselves preach “brotherhood” above all.

According to a National Council for Crime Prevention (Brå) report from 1999 however the vast majority of Hells Angels and Bandidos members held convictions, 22 percent of which were for violent crimes.