What we have learned is that it was a hand grenade thrown at a gate, but there are no injuries and no fire, says Hilda Andersson, command operator at the rescue service.
The alarm about the incident came in at 11:57 p.m. on Thursday. The emergency services had left the scene around 12:45 a.m.
The explosion damaged the building's entrance and a number of windows, the police wrote on theirwebsite . The area was cordoned off just before 2 a.m. while awaiting the police bomb squad.
People were housed in their homes in connection with the incident.
