The alarm was received just before midnight on Sunday, and police responded with several units.
Initially, the police said no signs of an explosion were found. However, after further investigation, “minor material damage” was found, indicating that something had been detonated on an upper floor, the police wrote on their website.
The police have cordoned off the property.
"We have found an object that could be dangerous," says Mikael Lindh, the on-duty police officer.
Residents have been evacuated and the National Bomb Squad has been called to the scene. There are no reports of anyone being injured.
