Officers responded to reports of shots fired near Van Ness Avenue and Clay Street in the city's Pacific Heights neighborhood at around 2:10 a.m., San Francisco police Lt. Troy Dangerfield said.
According to preliminary information, the victims were driving on Van Ness Avenue and were followed by a suspect vehicle, which pulled up alongside and someone from inside opened fire.
Five to seven shots were fired, Dangerfield said. It wasn't clear this afternoon what preceded the shooting.
Three men in the victims' vehicle were hit by gunfire. All three were hospitalized with wounds that were not expected to be life threatening.
The suspect vehicle drove off east on Clay Street. No one was arrested and no suspect or vehicle descriptions were available.