Swedish police in the southwestern city of Gothenburg say they have arrested four people suspected of plotting a terror attack.

The arrests were announced after hundreds of people were evacuated from Gothenburg's Roda Sten building late Saturday. The building is the venue of the city's biennial art exhibit.

Arts center officials said police ordered them to evacuate the building, then conducted a search of the building.

Police did not give details about the four arrested or the circumstances of the arrests.

It was not clear whether the arrests were linked to the 10th anniversary of the September 11 terrorist attacks in the United States.