The death toll rose to 36 from a huge fire that tore through a converted warehouse in Oakland, California during a dance party and investigators said on Monday they "absolutely believe" more bodies will be pulled from the rubble.
The cause of the blaze, which erupted late Friday in a building that was home to an artists' collective known as the "Ghost Ship", has yet to be determined. It was the deadliest fire in the United States for more than a decade.
"We are no closer to finding the cause and we absolutely believe that the number of fire fatalities will increase," Oakland Fire Battalion Chief Melinda Drayton told a predawn news conference at the site.
As criminal investigators joined recovery efforts at the charred two-story loft building, just east of San Francisco, firefighters have discovered the remains of some three dozen people as they picked through the debris-filled wreckage.
The crews temporarily halted work in the early hours of Monday due to fears that an external wall could collapse. About 70 percent of the building had been searched at that point, authorities said.
Drayton said contractors and structural engineers will develop a plan on Monday to determine how to continue recovery efforts safely.
Arson is not suspected, according to officials, but investigators are checking whether the building, which served as a base for the Ghost Ship Artists Collective and often hosted parties, had a history of code violations.
Oakland Mayor Libby Schaaf said the Alameda County District Attorney's Office has activated its criminal investigation team and a representative of the prosecutor's office is monitoring the recovery process. Schaaf said she was not authorized to say if a criminal probe was under way.
The city's first priority, the mayor said, was locating victims and supporting their relatives. As of Monday morning, 11 of the dead had been identified, police said.
Some of the victims were 17 or younger, although most were in their 20s and 30s, officials said. Some were from elsewhere in the country and abroad.
With many of the victims burned beyond recognition, families have been asked to preserve items that might contain their DNA to help identification.
Officials are still unsure how many people were inside when the blaze broke out.
The warehouse was one of many converted lofts in Oakland's Fruitvale neighborhood, a mostly Latino district where rents are generally lower than in the rest of city.
"HITS VERY CLOSE TO HOME"
Chris Nechodom, 30, said he was on the ground floor when he saw flames race across the ceiling. As he fled, he heard a loud noise and saw a plume of thick black smoke.
"It blew out maybe 10 feet out of the entrance," Nechodom said. "After that, I saw a few more people crawl out."
The building had been designated for use as a warehouse only, according to city officials, who were aware of reports that people were living there, although no permits had been issued.
Photos of the warehouse from before the blaze showed it filled with an array of musical instruments, statues and antiques. Furnished with sofas and colorful carpets, it featured a maze of side rooms and nooks.
The party took place on the second floor of the building, which appeared to have only two exits, officials said. There was no evidence of smoke detectors or sprinklers.
Police will use body camera footage from first responders, emergency calls and other information to help determine the cause of the fire and whether criminal charges should be filed.
"We have a lot of moving parts to this and we'll certainly find answers," Johnna Watson, a spokeswoman for the Oakland Police Department, told reporters on Monday.
It was the deadliest blaze in the United States since 100 people perished in a 2003 fire at a Rhode Island nightclub.
Exhaustion has been taking an emotional toll on fire crews who have worked around the clock. One of those killed was the son of a sheriff's deputy, said Sergeant Ray Kelly, spokesman for the Alameda County Sheriff's Office.
"This tragedy has hit very close to home," he said.