Firefighters were working to put out a fire Saturday evening that scorched 35 cars at an automobile lot in Fremont, officials said.

By about 5 p.m., the blaze had been contained to the cars at the Insurance Auto Auction, a used car dealership that auctions to highest bidders, at 6700 Stevenson Blvd. Firefighters were still working to put the inferno out, officials said.

There were no injuries. It is unclear what caused the fire.

Sarah Ravani is a San Francisco Chronicle staff writer. Email: Twitter: @SarRavani