UPDATE 5:33 p.m. EST:
Oakland Mayor Libby Schaaf said during a press conference that authorities will undertake a thorough investigation of the fires for the sake of the families.
Oakland Fire Chief Teresa Deloach Reed announced that authorities have still only confirmed nine fire-related fatalities. Twenty-five people in attendance at the party are still missing.
Authorities confirmed that a permit for a large party had not been issued.
UPDATE 3:06 p.m. EST:
During a press conference, authorities said that they are preparing for the possibility that the body count may rise to around 40 as they continue to search through the burnt warehouse.
Reports indicate that dozens of people were in the building when it caught fire, reports CNN.
WATCH | Oakland authorities' initial press conference
A fire broke out Friday night at a warehouse party in Oakland, California.
San Francisco Bay Area authorities have confirmed there are 'casualties.'
BREAKING: Fire officials say at least 9 people die, 13 missing in blaze at a warehouse party in the San Francisco Bay Area.— The Associated Press (@AP) December 3, 2016
It has left an undetermined number of people missing in a building in Oakland, California, city Fire Chief Teresa Deloach Reed said Saturday morning.
Authorities say structural damage is hindering search efforts.
Authorities told KTVU-TV about 50 people were inside the building.
Here's more footage of the deadly fire.
The Associated Press contributed to this report.