Six firefighters have suffered minor injuries in a fire that partially collapsed a three-story building in Jersey City. Authorities say the blaze started early Thursday morning and spread to nearby buildings, displacing some residents. Video showed intense flames and heavy smoke. Jersey City Fire Chief Jack Johnson says the injured firefighters are being treated at a hospital. The fire is under investigation. It was burning in the basement area, which couldn't immediately be reached. Officials are unsure if the building was occupied. Authorities are considering demolishing the remainder of the building.