Swedish police have arrested four people in the southwestern city of Gothenburg on suspicion of preparing a terror attack, local media reported, citing intelligence sources.
A spokeswoman for Sweden's SAPO intelligence agency, Sara Kvarnstrom, was quoted by the TT news agency as saying the arrests took place on the night of September 10.
Kvarnstrom said SAPO saw no reason to raise its terror alert level, which has been at "elevated" since October.
"Our assessment is that there is no reason for public concern at the moment," she told AP.
Police have given no details of the four arrested.
It's unclear if the suspected plot was connected with the 10th anniversary of the September 11 attacks.
The arrests were announced after hundreds of people were evacuated from Gothenburg's Roeda Sten building, venue of the city's art biennale.
A biennale official, Ulrike Sten, told reporters that the evacuation had followed warnings of a "possible threat."
The TT agency reported that the arrests took place near the biennale building.
compiled from agency reports