ANZA, Calif. -

Riverside County firefighters are battling a fast-moving vegetation fire that could threaten the Cleveland National Forest, which is home to the San Jacinto State Park.

Spokeswoman Melody Hendrickson said crews were called to extinguish an outbuilding that had caught fire near the intersection of Cary Road and Tripp Flats Road at 12:40 p.m. Friday. The fire quickly spread, she said, to the surrounding dry vegetation.

When you see news happen, send pictures and video to Newsline 3!

At 1:30 p.m., 25 acres had been scorched and one double-wide mobile home had been destroyed, Hendrickson said.

As crews work in the 87 degree heat and 12 mph winds to put out the fire, they're also trying to find out how the fire started.

Stay with KESQ.com and CBSLocal2.com for more on this developing story.