LOS ANGELES (Reuters) - A fast-growing brush fire prompted the evacuation of roughly 700 people on Tuesday from a mobile home park and nearby community in Southern California's Riverside County, state fire officials said.

The blaze erupted shortly before 12:30 p.m. local time and charred about 400 acres of drought-parched vegetation within three hours as flames roared through canyons and foothills in the Cherry Valley area, about 75 miles east of Los Angeles.

No property losses or injuries were reported. But sheriff's deputies issued mandatory evacuation orders for the Highland Springs Village Mobile Home Park and dwellings in the nearby Banning Bench community to the northeast, said Liz Brown, a spokeswoman for the California Department of Forestry and Fire Protection (Cal Fire).

The trailer park consists of roughly 200 homes, but the majority of the estimated 700 evacuees were from Banning Bench, she said.

As of late afternoon, winds were blowing the flames mostly away from both populated areas, "but we have them under evacuation because we have a ton of equipment coming in, and this is our access point to that fire," Brown told Reuters.

More than 320 firefighters were initially assigned to the blaze, dubbed the Bogart Fire, with reinforcements expected to arrive soon, according to Brown. The cause of the fire was under investigation.

She said temperatures that had reached into the low-triple-digits earlier in the day had subsided somewhat, but humidity remained low and winds were relatively light, at 5 to 10 miles per hour.

Cal Fire reported about 12,000 firefighters battling about 10 other large fires across the state on Tuesday, most of which were largely contained or burning in remote areas. To date this year, a total of 4,270 wildfires large and small have blackened more than 183,000 acres statewide, 30,000 acres more than at the same time last year.

(Reporting by Steve Gorman; Editing by Tom Brown)