On Tuesday evening, about 50 protesters illegally entered the Mediterranean Museum in central Stockholm.
The demonstrators had taken part in a permitted demonstration on Gustav Adolfs torg.
- We believe that there has been some kind of activity at the museum that aroused emotions in the protesters, said Ola Österling, press spokesperson at the Stockholm Police.
Two arrested
Two people have been arrested.
- The police have used violence to get the protesters out.
The two arrested have also used violence, stated Ola Österling at the police.
Outside the museum, there was still a "high tone" after the protesters had been taken out of the building.
But the police judged that the situation was under control.
At 21.15 the operation was completed.
The police will now review camera footage and question employees at the museum.
Preliminary criminal classification is violent riot and trespass.
The alarm came in at 19.25 on Tuesday.