Three women, two men and two children are involved.
Four of them have been taken to hospital, but the boy and the girl have not had to seek care.
The police remain at the scene.
- We do not know how long we are left.
Right now we are trying to get a picture of what has happened, says Petra Blomkvist, press spokesperson at police region Mitt.
According to the police, accessibility at the site is severely limited.