Stockholm police destroyed a bag containing explosives that was found in a park in the Swedish capital late on Sunday night and are investigating further, they said on Monday.

The incident took place less than three weeks before a Sept. 11 general election in which crime is set to be a major issue among voters.

“The police assess that the bag which was found on Sunday at Kungstradgarden contained an explosive charge,” the police said in a statement.

A preliminary investigation has been opened and no one has so far been taken into custody. The police gave no details about who might have planted the device or the possible target.

The park in central Stockholm where the explosive device was found had been among venues for the city’s annual Culture Festival, which ran from Aug. 17 to Aug. 21.

The area was cordoned off and the bag disarmed by the bomb squad. Authorities carried out a forensic examination in the early hours of Monday morning, the police said.

“Now all the components will be examined,” Erik Akerlund, chief of police for the city’s Norrmalm district said in a statement.

“It is only after a full examination at the national forensic centre that we will be able to say whether the dangerous object was functional.”