A massive fire during a party at an East Oakland artists' collective has killed at least nine people, firefighters say, but many more victims remain unidentified or unaccounted for as of Saturday morning. It's already being called possibly the deadliest single structure fire in Oakland history, if not the deadliest in California's history.

According to the Oakland Police Department, the blaze was first reported at 11:32 p.m. Friday night, at a two-story live/work building comprised of artists' studios and residences at 1305 31st Avenue, which is near International Boulevard.

The complex is known as Ghost Ship (not to be confused with the annual SF Halloween party), and while some media sources have referred to it as a "rave cave," the party appears to have been a fairly small-scale electronic music showcase in what is usually a live-work space that was home to about 18 people.

Upwards of 50 people were inside the building when firefighters arrived, KTVU reports, as the collective was hosting a party Friday evening. According to firefighters, the blaze had "heavy smoke" from the beginning, and they told the East Bay Times that most of the dead were found on the second floor, which was connected to the first floor with a "makeshift" stairwell.

Other reports say that as many as 70 people were on site when the fire broke out, and an event page for the party on Facebook, which featured headliner Golden Donna — a.k.a. Madison, WI-based electronic musician Joel Shanahan — showed over 100 people intending to attend, though that number is changing as more people are claiming to have gone. CBS 5 reports that Shanahan, who was performing at the time the fire broke out, was able to make it out of the building and survived.

The Alameda County Sheriff's Department tells ABC 7 they are preparing for up to 40 dead. They also report that access to the second floor was made difficult because of the stairwell, which was made of stacked wooden pallets.

One survivor named Mule who lived in the building, speaking to reporters, says the fire started "in the back left corner," and moved quickly. He told the East Bay Times he was unable to help an injured friend because "I literally felt my skin peeling and my lungs being suffocated by smoke. I couldn’t get the fire extinguisher to work.” He escaped with minor burns.

By 11:38, the blaze was escalated to a three-alarm fire, and by 11:58, the damage to the structure was severe enough that firefighters were ordered out of the warehouse.

As the Chronicle reports, at one point the building's roof collapsed, making the firefight all the more difficult.

The paper notes, of the interior of the space, "Pictures of the building portray a fantastical interior of tapestries, instruments, and hand-built, ornately carved ceiling and room structures."

Oakland Fire Chief Teresa Deloach-Reed tells the East Bay Times the building lacked smoke detectors or sprinklers, and that the cluttered first floor "was like a maze almost," adding "It was filled end to end with furniture, whatnot, collections."

According to a fire dispatcher, crews remain on the scene as of Saturday morning, watching for "hot spots" and searching the scene. A cause for the fire has yet to be determined, according to OPD.

As of 8 a.m. Saturday, as many as 25 people remained unaccounted for, and the Alameda County Sheriff's Coroner's Bureau has so far only confirmed nine deaths, though that number is expected to rise. Attendees have been posting to Facebook about those who remain unaccounted for, and one posted this updated list Saturday morning, which includes one of the musicians set to perform Friday night, SF-based Chelsea Faith, a.k.a. Cherushii.

Most of those missing are between the ages of 20 and 40, and the UK Metro has posted a collection of their photos culled from Facebook.

Deloach-Reed made comments, picked up by the Daily Mail, about a multi-agency task force that would be searching the building end to end Saturday. "The building is a huge building," she said. "There's going to have to be a methodical way we go about body recovery, and then also trying to find out where the fire started and how the fire's spread took place. ... We have not done a complete search of the building."

Oakland police are asking any friends or family members of those they believe were lost in the fire to contact the Coroner's Bureau at 510-382-3000.

Below, Deloach-Reed discusses how the scene will be searched.

Update: As of 10:45 a.m., authorities were not updating the confirmed number of dead, and investigators still are staying out of the building for fear of collapse and further hot spots. They are using a drone with thermal imaging technology to search for fire and examine the structure.

Update 2: Photos of the eclectic interior of the space before the fire have emerged that you can see here. And the East Bay Express is reporting that building inspectors were at the building as recently as November 14 responding to habitability complaints.

Update 3: The Chronicle spoke with a couple of survivors of the blaze who had attended the party and said it was a very calm and mellow affair, with just a few people dancing on the upper floor and a lot of people sitting on couches and talking.

One woman, 24-year-old Laura Hobbs, described the stairway situation thusly. "The building itself was an art piece. The walls were completely covered with makeshift pieces of wood, so finding the staircase if you’d never been there before was difficult because they had built it into the wall in a certain way... There’s so much happening all over the building, so it’s hard to tell where the path is to anything. It all felt very cramped. The second floor was very much right on top of the first... I can’t imagine how long it’d take 40 people to get out, even in a calm situation."

Her cousin also described the place as "truly the most intricate warehouse space I’d seen."

Update 4: As of Sunday the official death toll rose to 24, with 80 percent of the structure still left to search.

Related: Pre-Fire Photos From Inside Oakland's 'Ghost Ship' Collective, Which Was Cited Two Weeks Ago By Building Inspectors

Jay Barmann also contributed to this post. The post has been updated throughout.