About 1,800 firefighters continued to battle the 12,500-acre Eagle fire on Monday morning, authorities said.
The fire is burning on the Los Coyotes Indian Reservation and at Anza Borrego Desert State Park. It broke out about five miles east of Warner Springs on Thursday night and was 45 percent contained Monday morning, Cal Fire reported.
Five firefighters suffered minor injuries and one outbuilding has burned since the fire broke out, and an estimated $4.7 million has been spent battling it so far, the state agency reported.
California National Guard helicopters joined the fight Sunday, helping to shuttle firefighters to remote areas as flames moved northwest toward Borrego Springs. Cal Fire reported 82 fire crews have been fighting the flames by ground and air, using 67 engines, 15 bulldozers, 33 water tenders, 19 helicopters, eight air tankers and three helitankers.
Agencies assisting Cal Fire with staff, equipment and other resources
included the San Diego County Fire Authority, U.S. Forest Service, Bureau of Indian Affairs, San Diego County Sheriff's Department, California Department of Parks and Recreation, California Conservation Corps, and California Department of Corrections and Rehabilitation.
The Borrego Palm Canyon Campground and Trail have been closed, along with the Los Valley Boy Scout Camp.
The cause of the blaze remains under investigation.
City News Service contributed to this report.