A wildfire of unknown origin blackened scores of hilly acres in Dehesa today, prompting evacuations in a nearby residential neighborhood as crews fought the flames from the ground and air.

California Department of Forestry and Fire Protection spokeswoman Roxanne Provaznik says the fire is up to 60 acres in the Willow Glen area, southeast of El Cajon.

The blaze began spreading through light brush and dry native grasses near Willow Glen Drive and Singing Hills Country Club in the Dehesa area shortly before 1 p.m., according to Cal Fire.

As the flames spread over a hillside near a U.S. Fish and Game Department shooting range, sheriff's deputies evacuated homes along Vista Sierra Drive, said Roxanne Provaznik, a spokeswoman for the state agency.

One firefighter suffered a minor injury while battling the blaze, which grew to more than 60 acres within an hour, Provaznik said.

Ground crews from several area agencies worked to corral the blaze with help from air tankers and water-dropping helicopters.

Provaznik says the fire is spreading at a moderate rate toward homes. About 300 firefighters are working the fire, which is being fanned by a mild west wind.

Westerly winds in the area were moderate and not a serious factor in the spread of the fire, according to Provaznik.

Watch News 8 and visit cbs8.com for further updates in this developing story.