It was just before half past six when a loud bang was heard in the residential area in Angered in northeastern Gothenburg.
It's clear that you get scared when something like this happens, says a person who lives nearby.
He woke up to the bang, which he describes as a loud rumble that continued to reverberate for a long time afterwards.
On site, the police could determine that it was a hand grenade that had exploded. No one was physically injured.
There are several windows that are broken, but it's only material damage, fortunately, says Thomas Fuxborg, press spokesperson for the police.
There were three children and two adults in the apartment, all are unharmed but naturally shaken.
During the night, an explosion also occurred in Partille outside Gothenburg, when something believed to be a hand grenade was thrown onto a balcony in an apartment building. No one was injured and according to the police, only minor material damage occurred.
The police are investigating whether and how the events are connected.
There are information in the investigations that make us see a connection, a link, says Göran Sundström, at the police department for serious crimes in Greater Gothenburg, to Göteborgs-Posten.
The events are classified as gross general endangerment.