Death toll rises to at least 36 from California warehouse inferno

Recovery teams examine the charred remains of the two-story converted warehouse that caught fire killing dozens in Oakland, California, US, December 4, 2016. [Photo/Agencies]

OAKLAND - The confirmed death toll from a blaze that engulfed a converted warehouse during a dance party in Oakland, California, rose to 36 on Monday, the greatest loss of life from a US fire in over a decade, as investigators sifted through charred ruins being treated as a crime scene.

Authorities said they were certain to find more bodies in the gutted building and were still trying to account for some 50 people reported missing by loved ones, although officials predicted the death tally would not climb drastically higher.

The cause of the fire, which erupted late on Friday in a sprawling two-story building leased to an artists' collective, has yet to be determined.

Officials have said arson was not immediately suspected. But Alameda County District Attorney Nancy O'Malley told an afternoon news conference that a potential criminal case could ultimately encompass charges ranging from involuntary manslaughter to murder.

One thrust of the investigation was expected to focus on possible safety violations at the site, which city officials said was already under investigation for reports of illegal construction.

Investigators from the US Bureau of Alcohol, Tobacco, Firearms and Explosives identified an "area of interest" on the ground floor that was still out of reach, according to Sergeant Ray Kelly, a spokesman for the Alameda County Sheriff's Office.

He described the spot as located to the rear of the warehouse where makeshift studios and cubicles were clustered.

O'Malley said fire investigators and a task force from her office were working with recovery teams inside the wreckage to preserve any potential criminal evidence as they comb through rubble for signs of victims and clues to origins of the blaze.

Deputy Fire Chief Darren White said his crews were removing debris "bucket by bucket," but a large construction crane was also brought to the scene, requiring electricity lines in the vicinity to be shut down as a precaution for several hours.