Los Angeles, Aug 3 (IANS): A fast-growing wildfire in Riverside County of Southern California forced around 8,000 local residents to be evacuated, the authorities said.

The blaze, dubbed "Apple Fire," which started Friday night, 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), Xinhua news agency reported on Sunday.

A total of 1,360 firefighters are battling on the scene, but they have been unable to contain any of it so far.

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, fuelled by hot and dry conditions with low humidity levels and gusty winds.

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.