There were people at home, both adults and children, but there were no injuries, says police spokesman Daniel Wikdahl.
The alarm about the incident, which Expressen was the first to report, came shortly after midnight.
"We have assessed that there is damage to the facade, but there is no danger of collapse. No one has been injured," says Tommy Wållberg, command officer at the rescue services, to TT.
The incident is being investigated as a serious act of public destruction and a serious violation of the Act on Flammable and Explosive Goods. The National Bomb Protection Service is working at the scene together with the police.
They take a look at what it looks like and use their expertise to try to find out what happened. If necessary, they also take care of other possible dangerous objects at the scene, says Daniel Wikdahl.
