Over 1,300 firefighters were battling a fast-growing wildfire burning out of control on Sunday in Riverside County of Southern California.

The blaze, dubbed "Apple Fire," forced around 8,000 local residents to be evacuated, the authorities said.

The fire started on Friday night and has scorched 20,516 acres (83.1 square km), according to the latest information updated by the California Department of Forestry and Fire Protection (Cal Fire).

A total of 1,360 firefighters backed by helicopters are battling on the scene, but they have been unable to contain any of it so far. Water-dumping planes and trucks were working to put out the fire.

The Apple Fire was first reported as two small fires near Cherry Valley, about 110 km east of Los Angeles downtown, and then spread very fast, fueled by hot and dry conditions with low humidity levels and gusty winds.

There were no reports of casualties. A single family home and two buildings were destroyed by the fire, the fire department tweeted. An investigation is underway to find out the cause of the fire.

Six helicopters and six air tankers were assigned to launch so called "air attacks" against the fire, which is threatening 2,500 homes, local NBC news channel said, estimating 19,000 gallons of flame retardant were used on Saturday.

Cal Fire's statewide fire map shows over a dozen wildfires are burning on Sunday.