Two men in their 20s were seriously injured and are being treated in hospital. They are not critically injured.
The police cordoned off the area and checked people and vehicles. Several people were detained in connection with this.
Six people were detained during the night, says police spokesperson Daniel Wikdahl.
He does not want to elaborate on whether the individuals were only taken in for questioning or if they are suspected of crimes.
The police suspect that there are links to serious organized crime.
The shooting took place on Rissne Square, and in connection with the incident, a restaurant suffered damage to its facade.
An investigation has been initiated into suspected attempted murder and serious weapons offenses. The alarm was raised at 22.16.
