The alarm about the incident came in just after 5pm on Sunday afternoon after calls about loud explosions in the area.
– We can quickly locate the place, there is a smell of smoke in the stairwell and in the basement we find the remains of a powerful firecracker, a so-called banger, says Evelina Olsson, press spokesperson for the police in the South region.
There are no reported personal injuries and the police have drawn up a report of vandalism.