SAN DIEGO (CNS) - Firefighters from the U.S. Forest Service and Cal Fire battled a two-and-a-half acre brush fire near Palomar Mountain on Sunday along the seven mile marker at Palomar Mountain State Park, just south of East Grade Road.

Firefighters knocked down the blaze's "forward rate of spread," the USFS said.

Air tankers initially were helping ground crews fight the blaze, but have since been released.

No injuries have been reported and the cause of the fire is under investigation.