Police in Sweden says five people sustained minor injuries when a blast occurred in an industrial area northwest of Stockholm, Fox News reported.

Police in the Swedish capital say the blast took place shortly after midnight Wednesday at an industrial building, shattering its glass windows as well as those at a nearby hotel in Vinsta. A number of cars also suffered damage.

It wasn’t immediately clear what caused the explosion.

A police statement Wednesday said three people received medical treatment on the spot while two others were taken to a local hospital.

The area was sealed off and forensics were at work on the scene.

No arrests have been made. The blast was not believed to be terror-related.