The San Francisco Chronicle ( http://bit.ly/12ScScU) says gunfire erupted Sunday afternoon at the 439-unit Lion Creek Crossings complex.
The girl died at the scene. The boy is at Highland Hospital with non-life-threatening wounds.
The gunman is described as a 13- to 16-year-old boy.
A teen boy was shot to death at the east Oakland complex in July.
Information from: San Francisco Chronicle, http://www.sfgate.com