The alarm about the object came at 12 noon. Two hours later, bomb disposal experts had carried out a controlled explosion and lifted most of the cordons.
In photos from the scene, the object appeared to be some kind of hand grenade.
"The initial assessment is that it is a live hand grenade. Further investigations will be carried out to see if this can be confirmed," says Filip Annas after the explosion.
A minor closure remains in place for the technical investigation.
"We will now investigate what happened and what the intended goal is. We have no direction there, but we are investigating without prejudice," says Annas.
The VMA (important message to the public) that went out has been withdrawn after the explosion.
The object was found outdoors.
"It was the public who noticed this, which is great considering that there are quite a few people on the move today," said police spokesperson Evelina Olsson earlier on Friday.
