UPDATE: The U.S. Forest Service says the fire has forced the temporary closure of a portion of Highway 178 in the Kern River Canyon.

The fire is estimated to have burned an estimated 600 acres and 20% contained. Traffic is being detoured onto Breckenridge Road/Highway 218, just east of Highway 178, and onto Kern Canyon Road.

There are no evacuations at this time, and no structures are threatened.

6 air tankers, 4 air attack planes, 5 helicopters, 13 hand crews, 20 engines, 2 water tenders and 4 dozers are battling the blaze.

ORIGINAL: Kern County Fire crews are on scene of a grass fire in the Kern River Canyon, near Highway 178 and Borel Road.

KCFD says the fire was 20 acres when originally reported, but Cal Fire is reporting that the fire has grown to 200 acres..

No structures are threatened and the blaze has a moderate rate of spread. This story is developing, check back for updates.