Firefighters at noon were battling a three-alarm blaze at a former go-go bar and apartment building just north of Chinatown.
The fire broke out about 11:36 a.m. at the J&J Trestle Inn at 11th and Callowhill Streets. Firefighters were on the scene three minutes later, said Capt. Carl Grymes, a fire department spokesman.
Flames leaped from the roof and thick smoke poured from windows on the building's upper floors.
Shortly before noon, the fire department sounded evacuation tones clearing the three-story building of firefighters. Traffic was blocked between 10th and 12th Streets on Callowhill.
Residents from down the street said the bar had closed about a year ago and was undergoing renovations, possibly by new owners.
It esclated to a third alarm about 12:15 p.m. and was placed under control at 12:42.