The fire started during an electronic music party inside a converted warehouse in Oakland Friday night.
Dozens remain unaccounted for and authorities fear the death toll could rise dramatically.
Hours after this deadly fire the cause still remains unknown.
Authorities believe about 50 to 100 people were inside the building when the fire began.
Intense orange flames ripped through a warehouse in Oakland, California. At least nine people are dead and authorities fear the death toll could rise as high as 40.
"This is a very tragic event. Our hearts all go out to not only to the families, but our community," said Johanna Watson of the Oakland police.
"There's still a lot of the building that needs to be searched, and as we continue to search the building, I pray that our fatality count does not go up, but I believe there is a lot of potential for it to," said Teresa Deloach Reed, Oakland fire chief.
Oakland officials said the fire broke out about 11:30 p.m. The warehouse located in the San Francisco Bay Area was converted into artist studios. It was extremely cluttered with furniture, mannequins and statues. Police said an electronic music party was taking place at the time of the blaze.
"The roof has collapsed down onto the second floor. So we have to literally go in there, piece by piece, and move wood and timbers and debris," said Sergeant Ray Kelly, Alameda County Sheriff.
The Oakland fire chief said there was a single makeshift staircase connecting the two floors of the building, and that it was made out of wooden pallets.
"There was only one way up and one way, you know just the one way up and down from the second floor,” she said.
It took roughly five hours to put out the fire in the building, which reportedly did not have sprinklers. Officials haven't recovered one body however, they said the building is still considered to be unsafe.
“We’re going to put up some drones, UAVs, unmanned aerial systems with small, little drones with thermal imagers. We'll use those to see if there are any more hot spots there. We'll address those hotspots. At that point, once the building is somewhat safe for us to go in, our coroner’s personnel will go in and begin the recovery process,” said Kelly.
Police said they have talked to people who came out of the warehouse and either left prior to the fire or were able to get out.