A group of young boys attacked several other audience members at Palads cinema at 20:45 on Thursday during the showing of the rapper drama 'Ækte vare' ('Flow'), Metroxpress reports.
A police spokesman said the brawl escalated when the group were told to lower their voices.
Some movie-goers were taken to hospital with bruises and cuts after the boys hit them on the head with a blunt object.
Boys escaped
An eyewitness said it took three to four minutes before the guards arrived.
The thugs, who eyewitnesses described as being of Middle Eastern appearance, managed to escape the police and are still on the loose.
They were last seen leaving the city square by bus.
