By Kimberly Hutcherson and Dan Simon
OAKLAND, Ca. (CNN) -- A fire broke out Friday night during a party at a two-story warehouse and artists' studio in Oakland, killing at least nine people and leaving about two dozen missing, the California city's fire chief said.
Initial reports indicate dozens of people -- perhaps up to 100 -- were in the building when the fire started, Oakland Fire Chief Teresa Deloach Reed said.
Most of the dead were on the second floor, where people would have had difficulty leaving because one stairway -- made of pallets -- was the only way down to the floor below, Reed said.
"It must have been a very fast-moving fire," she told reporters Saturday morning.
"There wasn't a clear entry or exit path up on the second floor. ... If (the fire) had started in that area (by the stairwell), then everyone on the second floor" would have had trouble escaping, she said.
An electronic-music party was happening at the building at 1305 31st Ave. Friday night, a Facebook event page says. People were using that page Saturday to post names of those who are believed to have attended.
Twenty-five people are unaccounted for, as reported by people who either escaped the fire or believe they knew someone who was there, Reed said.
"We don't know if any of them went someplace else, self-transported to the hospital," Reed said.
Firefighters were called to the building around 11:30 p.m. PT, the fire department said. Details about what led to the fire weren't immediately available.
Firefighters have not been able to search the entire building; crews, possibly with heavy equipment, first will have to remove debris and make sure the building is safe for searching, Reed said.
Terry Lightfoot, a representative of Oakland's Highland Hospital, told CNN that the hospital received two patients and one of them has been discharged. Lightfoot did not know the condition of the patient who remained hospitalized.
An artists' studio
Reed said the building "was kind of like an artist studio" that had partitions where artists worked.
She said she has heard reports that some people may have been living there, but there were no bedrooms, per se. It wasn't clear how many people lived there, if anyone, she said.
The Alameda County Sheriff's Coroner's Bureau has been called to the scene.
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