20-acre brush fire threatening homes in west Los Angeles

An unknown number of homes were under "immediate threat" on both flanks of the blaze, south of Yoakum Drive and north of Portal Drive, according to the L.A. Fire Department. The fire was moving toward Benedict Canyon Drive, the agency added.

Residents along San Ysidro Drive between Millboro Place and Beeson Drive needed to evacuate, LAFD Capt. Branden Silverman tweeted. The evacuation area included Beeson Drive and Millboro Place west of San Ysidro Drive.

"The fire has burned down and then could be making the run up that hill, up that hillside, which is why that community is under evacuation," LAFD spokeswoman Margaret Stewart explained.

Officials set up an evacuation center at UCLA's Wooden Center.

No injuries have been reported.

More than 150 firefighters were assigned to the incident. LAFD said the county fire officials also sent air and ground resources.

Firefighters were facing warm, dry conditions in the hills, according to the National Weather Service.

The forecast called for highs of 84 to 87 degrees, with humidity of about 35 percent. Light winds of 7 mph were blowing in a southerly direction, with gusts of up to 14 mph expected.

Plumes of thick, light-colored smoke towered above the hills and were visible for miles around Los Angeles and beyond.