The explosion occurred inside the stairwell, according to the police. No one was injured.
There are several doors and windows that are broken, said Gustaf Sandell, officer in charge at the rescue service, to Sydsvenskan shortly after the alarm about the explosion, which came at 23.42.
During the night, the police's bomb technicians and forensic experts have investigated the scene. The police have also conducted interviews and searched with, among other things, a dog.
No one has been arrested, the police write on their website on Friday morning. The incident is being investigated as gross endangerment and gross violation of the law on flammable and explosive goods.
On Wednesday evening, around the same time, there was an explosion just a few hundred meters away from the site. That explosion caused material damage, but no one is said to have been injured. Among other things, windows to a store were shattered, as well as facades and vehicles.
Four people aged 16-21 were arrested during the night to Thursday, suspected of gross endangerment. One of them was later released and the other three were detained.
