The incident was reported at 10 p.m. on Friday when police received several calls about banging. An injured person was found and taken to hospital, but neither police nor the Swedish Prosecution Authority has any information about the extent of the injuries.
A 25-year-old man was arrested overnight.
The arrested person is being held on probable cause on suspicion of attempted murder, says Annie Nilsson at the Public Prosecutor's Office's press service.
A major police operation was underway on Friday evening and all train traffic to and from Gävle was temporarily stopped.
