OAKLAND, Calif. (AP) — At least nine people died in a blaze that broke out during a party in a converted warehouse late Friday night in the San Francisco Bay Area, according to fire officials.

Oakland Fire Chief Teresa Deloche-Reed said at least another 25 people are unaccounted for as of Saturday morning. Authorities are working to verify who was in the building when the fire broke out.

Deloche-Reed said the roof collapsed and that fire investigators will have to search through debris to find any remaining bodies.

Authorities are working to verify who was in the building when the blaze broke out around 11:30 p.m. Friday. It tore through the building during an event featuring musician Golden Donna's 100% Silk West Coast tour, the East Bay Times reports.

Oakland firefighters tweeted video of flames pushing through the roof.

The fire chief said what started the fire is unclear, but that there did not appear to be sprinklers in the building.

Authorities told KTVU-TV about 50 people were inside the building, which houses a group of artists and their studios.

"It was too hot, too much smoke, I had to get out of there," Bob Mule, a photographer and artist who lives at the building and suffered minor burns, told the East Bay Times. "I literally felt my skin peeling and my lungs being suffocated by smoke. I couldn't get the fire extinguisher to work."

People used a Facebook page Saturday to post and seek information on family and friends who may have been in the building.

Oakland police urged those concerned about missing people to call the Alameda County Sheriff's Coroner's Bureau at 510-382-3000.

The office said the coroners were also at the scene Saturday morning and unavailable for comment.

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Associated Press writer Adam Kealoha Causey in Phoenix contributed to this report.