An explosion took place outside a gate to a multi-family house in Gamlestaden in Gothenburg on Sunday evening, the police write on their website.
No one is reported to have been injured, but the explosion has caused damage to parts of the facade, according to the police.
During the night, the area was cordoned off and the police are searching with, among other things, a helicopter for one or more perpetrators.
The incident is being investigated as general reckless destruction.
