Two-alarm fire knocked down in San Francisco's Cole Valley

SAN FRANCISCO (KTVU and wires) -- Firefighters in San Francisco have knocked down a two-alarm fire at a duplex in Cole Valley.

The fire at 1050 Clayton St. was first reported some time shortly after 8:30 p.m. according to a fire department dispatcher.

Flames completely engulfed the duplex, but crews were able to contain the fire and knock it down by 10 p.m. 

Fire officials haven't said yet if anyone was home at the time.

The cause of the fire is under investigation.