Update Tuesday 6:09 p.m.
The shooter was still at large Monday evening, police said, according to NBC-LA.
Police did not know a motive, NBC-LA reported, but the shooting began after a confrontation between the gunman and another person inside Subway.
A gunman opened fire at a Subway restaurant in San Bernardino Monday afternoon, injuring at least three people, NBC-LA reports.
The shooter was still at large as of 1:45 p.m., police said.