The shooting happened at about 10:30 p.m. at the Ping Yuen public housing complex in the 800 block of Pacific Avenue, where the girl lives, police spokesman Officer Samson Chan said.
According to Chan, the girl was at the playground with her mother.
When the mother stepped away for a moment to go to their apartment, she heard gunshots and ran back to the playground to find her daughter shot in the leg, Chan said.
Officers responded and canvassed the area, and detained a group of seven youths nearby, Chan said.
One member of the group, a 17-year-old boy, ran from police but was detained and arrested after a 9mm handgun was found on him, Chan said.
All of the juveniles are from San Francisco but none lived in the complex, Chan said.
The 17-year-old boy was booked on gun charges, Chan said. He said additional charges will be filed if forensic tests indicate the gun found on him was used in the shooting.
The injured girl was taken to San Francisco General Hospital, according to Chan. Her wounds were not considered life-threatening, but he did not know her condition today.
Ari Burack, Bay City News