A large structure fire at a warehouse concert in Oakland on Friday night has left at least nine dead, with dozens more reported missing — among them two UC Berkeley students.

The fire took place at 1305 31st Ave. in Oakland during a performance headlined by electronic artist Golden Donna, according to an Oakland Police Department press release. Friends of UC Berkeley students Jenny Morris and Vanessa Plotkin have reported them to be missing. UC Berkeley alumni Griffin Madden and David T. Cline have also been reported missing.

Seung Lee, a UC Berkeley alumnus and former Daily Californian online managing editor, attended the event briefly before leaving with his friends to purchase drinks at a nearby liquor store. When they returned, flames were erupting from the warehouse.

“We just saw this thick black smoke just coming out of the front windows at a very furious pace,” Lee said.

It took about four hours for firefighters to put out the blaze, which began about 11:15 p.m. and caused the roof of the building to collapse. Oakland Fire Department is working with federal partners to determine the cause of the fire, according to a press release.

“Due to structural damage from the fire, the ongoing investigation efforts and search for additional victims will be methodical and are anticipated to take some time,” said Oakland Fire Chief Teresa Deloach Reed in a press release.

The presence of some foreign attendees at the venue may complicate the Alameda County Sheriff’s Office’s efforts to reach out to families.

Deloach Reed told the East Bay Times that the building did not appear to have sprinklers and that crews did not hear any fire alarms when they entered the building.

The Alameda County Sheriff’s Coroner’s Bureau and chief forensic pathologist are working to process the scene and release the identities of victims.

The majority of bodies were found on the second floor of the building, which was connected to the bottom by a narrow stairwell. The warehouse was an artists’ collective that frequently held art shows.

After the fire broke out, people gathered at a Wendy’s parking lot across the street to watch the scene unfold.

“There were a lot of people holding each other — there were some people kind of crying and wailing and just saying, ‘Oh my god, oh my god,’ ” Lee said. “That’s one of the hardest parts — it’s the fact that you know maybe they knew that they had people inside there.”

There were allegations of code violations on the building this year, including one that reported piles of trash and illegal building on the warehouse. Oakland’s city planning department had opened an investigation into reports of garbage accumulation Nov. 13 and later confirmed the reports, said Darin Ranelletti, Oakland’s director of planning and building, at a press conference.

According to Ranelletti, having a party at the warehouse would have required a permit from the city, but no permit was issued for the event held Friday night. He added that additional reports were made that people had been living in the warehouse.

The Alameda County Coroner’s Bureau and the American Red Cross have organized a Family Assistance Center at 2425 East 12th St. in Oakland, with grief counseling and resources for families affected by the tragedy. Family members and friends looking to locate missing persons may go to the center or call 510-382-3000.

“Last night’s fire was an immense tragedy,” said Oakland Mayor Libby Schaaf in a statement. “I am grateful to our first responders for their efforts to deal with this deadly fire. Our focus right now is on the victims and their families and ensuring that we have a full accounting for everyone who was impacted by this tragedy.”

Check back for updates.

Staff writers Chantelle Lee and Harini Shyamsundar also contributed to this report.

Contact Jessica Lynn and Cassandra Vogel at [email protected].

Correction(s):

A previous version of this article incorrectly stated that the fire was extinguished about 11:30 p.m. In fact, the fire began about 11:15 p.m.

A previous version of this article incorrectly stated Griffin Madden is a UC Berkeley student. In fact, Madden is a UC Berkeley alumnus who graduated in 2015.