Some 6,000 residents have been ordered to evacuate in the face of a raging wildfire near Palm Springs in California, officials said Thursday.

Nearly 3,000 firefighters are battling the so-called Mountain fire, which has ravaged some 22,800 acres in the San Bernadino National Forest east of Los Angeles, and is only 15 percent contained on its fourth day.

Some 4,100 homes are threatened by the blaze, as well as 100 commercial properties, said US Forest Service spokesman John Miller.

The most active parts of the blaze are above the town of Idyllwild and near Trails End, to the southwest of Palm Springs, a celebrity-retiree oasis city two hours' drive to the east of Los Angeles.

"These two areas will be the focus of today's firefighting activities as both air and ground crews work to slow the rate of spread of the fire," Miller said.

The Palm Springs Aerial Tramway, a popular tourist cable car which takes visitors from the baking desert floor straight up to the much cooler Mount San Jacinto State Park, was closed due to smoke from the wildfire, it said on its website.

A total of 2,985 firefighters, 228 fire engines, 10 fixed-wing aircraft, 17 helicopters, 21 water tenders and 15 bulldozers are involved in fighting the blaze, the latest in a particularly active wildfire season in the western United States.

Three weeks ago 19 firefighters were killed when overcome by flames in a fast-moving blaze in neighboring Arizona, making it the most deadly wildfire since 29 died fighting a blaze in Los Angeles's Griffith Park in 1933.