Authorities say the incident happened at the 24-hour Subway on Central Avenue south of Manchester Avenue at about 1:30 a.m. An assault rifle, possibly an AK-47, was used in the robbery, according to LAPD Sgt. James Winter.
As the men left, they forced a female customer into her car to get to their getaway vehicle, which was a few miles away. Police say the woman was physically unharmed but shaken.
Investigators believe they know the identities of the two suspects, who remain at large.
Police have not released how much money was taken from the Subway.
City News Service contributed to this report.