The stubborn blaze began about 5 a.m. at a single-store structure in the 1300 block of Margo Street, where crews initially attacked the flames from atop the structure. About thirty minutes later, firefighters abandoned the rooftop and went into a defensive mode, dousing the fire with water cannons mounted on aerial ladders.
The business was "filled with densely stored clothing," the LAFD said in a statement.
There were no reports of injuries, and the fire was prevented from spreading to adjacent buildings.
The blaze was fully extinguished about 8:30 a.m., the Fire Department said.
The cause of the fire was not immediately known.
The Los Angeles Police Department urged motorists to avoid the intersection of Pico Boulevard and Olive Street, which was closed with more than a dozen fire engines at the scene.