The fire was reported at 3:58 a.m. on Divisadero Street, between Oak and Page Streets, the dispatcher said.
The blaze was located toward the rear of a wooden building and was brought under control by firefighters at about 5 a.m., fire officials said.
Firefighters remain on the scene and motorists are advised to avoid the intersection.
No injuries have been reported and the cause of the fire remains under investigation, according to fire officials.
