Police were called out to the building at the Mariatorget square on Södermalm at 3.37am after receiving reports from people hearing “a sound described as a powerful bang”, a statement said.
They were able to confirm that the detonation had caused damages to the staircase area and an apartment door in the building, but said there was nothing indicating anyone had been injured.
“Police at the scene are making sure that those who have to leave their apartments can do so even though the national bomb squad and forensic teams will be working in the stairwell,” police said.
It remained unclear on Monday morning what had detonated and why.
The building is owned by the Swedish Academy, the scandal-hit body that hands out the Nobel Prize in Literature, through a trading company. Local newspaper Mitti reports that several Academy staff members are registered as living in the building. It is however not known if the Academy was the intended target.
Swedish Academy's permanent secretary, Anders Olsson, told public broadcaster SVT that as far as he knew no threats had been made against the Academy or its staff members.