JULIAN, Calif. -

Hundreds of firefighters today battled a roughly 2,500-acre wildfire that has forced residents from their homes southeast of Julian, authorities said.

The so-called Chariot Fire broke out just before 1 p.m. Saturday east of Sunrise Highway and about 9 miles southeast of Julian, according to Cal Fire. The agency reported that as of early Sunday evening, the fire was 20 percent contained and threatening at least 20 residences.

Four minor injuries were reported by Cal Fire, which said 871 firefighters were assigned to battle the blaze. In addition to the state firefighting agency, the U.S. Forest Service, California Highway Patrol, San Diego County Fire Authority, San Diego County Sheriff's Department and California State Parks were helping with firefighting and road closures.

The Horse Heaven Campground in the Cleveland National Forest was evacuated, as were the El Prado, Laguna and Al Bahr Shrine campgrounds on Mount Laguna, Cal Fire officials said.

Evacuees were directed to an emergency shelter set up by the American Red Cross at Joan MacQueen Middle School at 2001 Tavern Road in Alpine.

State Route 79 was closed at Sunrise Highway, Sunrise Highway was closed at Old Highway 80, and the Kenwood Drive onramp to state Route 94 was closed, according to the California Highway Patrol.

The cause of the fire was under investigation.