Stockholm - A powerful blast rocked an apartment building in the southern city of Malmo early Friday, but no-one was injured in the explosion, police said.

Police and emergency services said the likely cause was a bomb after ruling out a gas leak, but had no information about any specific threats.

Local news media reported that a witness had spotted a car leave the scene shortly before the explosion.

The blast destroyed most of the doors in the four-storey building, and several apartments were also damaged by debris.

Some 30 people in the building were evacuated, and several were treated for shock. (dpa)