A male passenger was injured by either bullets or broken glass Thursday while riding a San Francisco Municipal Railway bus in the city's Potrero Hill neighborhood, a police spokesman said.
The shooting was reported at 2:14 p.m. in the area of 25th and Wisconsin streets.
The victim suffered a grazing wound and is expected to fully recover.
Police said three men boarded an inbound 19-Polk Muni bus in the area, then got off the bus and fired multiple shots into the vehicle, police spokesman Sgt. Dennis Toomer said.
The male passenger was struck and was taken to San Francisco General Hospital by the Muni driver, Toomer said.
The bus stayed at the hospital for evidence gathering.
The suspects had not been found as of 2:45 p.m., Toomer said.
Wisconsin Street was closed between 25th and Carolina streets this afternoon because of the investigation, he said.
San Francisco Municipal Transportation Agency officials posted on Twitter that the agency's 10-Townsend, 19-Polk and 48-Quintara lines are being rerouted around the area because of the police activity.
Anyone with information about the shooting is asked to call the Police Department's anonymous tip line at (415) 575-4444 or to send a tip by text message to TIP411.
Bay City News contributed to this report.