Gunfire broke out around 1:30 a.m. at San Francisco's 330 Ritch Saturday morning. Three men were wounded, one critically.
Police said the shooting took place after an argument ensued at the popular SoMA nightclub, which often hosts well-known electronic acts.
The victims were taken to San Francisco General Hospital, where they are currently being treated. They were identified only as East Bay residents in their 20s.
Witnesses said the gunfire began inside the club and then continued as a mob spilled onto the street. One bystander said at least 30 rounds were fired.
"My friend grabbed me, pulled me, before you know it shots were fired," Tyresa Leader told the Associated Press. "People were down. People were screaming. People running in and out of the club. Blood on the floor, people falling, people screaming."
Investigators are currently processing evidence, and no arrests have been announced.