UKIAH (CBS SF) — Officials say fire crews are making progress in battling a wildfire burning outside the northern California city of Ukiah.

Cal Fire spokesman Daniel Berlant says since the fire was reported around 1:30 p.m. Saturday, it has consumed about 400 acres, or a little more than half a mile. The blaze is 55 percent contained.

More than 500 firefighters are battling wildfire, which is burning in an area of heavy brush and forest east of Ukiah. Four helicopters and three air tankers have also been called in to help.

The cause of the fire is under investigation. Berlant says no homes are threatened.

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