We received a large number of calls at 01 hour and it turned out that something had been thrown in through a window in an apartment and then exploded, says Joakim Björkkvist, duty officer at police region South.
Two people were in the apartment.
They were not physically injured, says Filip Annas, the police's press spokesperson.
A man in his 20s was arrested during the night and detained after a decision from the prosecutor. He is suspected of attempted murder and a crime against the law on explosive and flammable goods.
It is unknown what has exploded and how large the damage is.
The window is broken but I do not know how bad it is inside the apartment. We have not needed to evacuate anyone, says Joakim Björkkvist.
The scene was cordoned off for a technical investigation during the night.
