Officials said a man hit the El Michoacano Market on the 1400 block of 243rd Street.
The suspect entered the store wearing a black or blue bandana over his face and demanded money in Spanish. Police said he attempted to shoot a 12-gauge pump-action shotgun.
There was no word on whether he got away with any cash or how much.
The LAPD issued a community alert after the incident, telling residents to be wary of the dangerous suspect.
The suspect was said have fled in a gray or white 1990s Chevrolet Astro van or a tan 1990s Ford Explorer.