500 acres burned as firefighters battle brush fire in Perris

PERRIS, Calif. (KABC) -- Firefighters battled a fast-moving brush fire that grew to 500 acres in Perris Wednesday.

The Rock Fire was reported shortly after 2:30 p.m., near the Lake Perris State Recreation Area, according to the Riverside County Fire Department.

Water-dropping helicopters and air tankers slowed the fire's progress.

Fire officials said the blaze had charred 75 acres just after 3 p.m., but by Wednesday night it had grown to 500 acres and was 75% contained.

It's unknown what caused the fire. No evacuations were ordered.