BISBEE — Bisbee Mayor David Smith says a fire at City Hall means city offices will have to be temporarily relocated.

Authorities say the fire early Wednesday caused substantial damage to City Hall.

City offices will be relocated to Cochise County office buildings on Melody Lane.

Fire investigators said an investigation of the blaze will begin Friday. Investigators won’t be able to make safe entry into the building until a structural engineer first checks it out, said Carol Capas, spokeswoman for the Cochise County Sheriff’s Office.

Bisbee Police Chief Albert Echave said no one was in the building when the fire began around 1 a.m. Wednesday and that there were no injuries.

At least seven other fire departments helped Bisbee firefighters battle the blaze in the southeastern section of the town.

The building was constructed in 1906, Capas said, originally as headquarters for the Phelps-Dodge mining company, and the city began using it in the 1930s. Bisbee is 80 miles southeast of Tucson. Smith is a former Tucson police officer.