A 14-year-old girl opened fire with a handgun in the crowded cafeteria of a Catholic school in Pennsylvania yesterday.
She wounded a female classmate in the second US school shooting in three days.
The first school shooting in recent years to involve a female suspect unfolded at Bishop Neumann High School in Williamsport when Elizabeth Bush allegedly walked up behind 13-year-old Kimberly Marchese in a crowd of 115 students and shot her in the right shoulder with a .22 handgun.
Ms Marchese is in hospital in stable condition at a regional trauma center.
Williamsport police detective Mr David Ritter told a news conference: "It is our information that the victim was seated inside the cafeteria during the lunchtime and the other individual walked up and shot her in the shoulder, one time, with a handgun."
Bush allegedly brought the weapon to school from her parents' home near this central Pennsylvania community of 31,500, located about 192 km northwest of Philadelphia.
The two girls apparently had been feuding. Investigators described Bush as a shy teenager who transferred from public school a year ago because of harassment only to face more clashes with her new classmates.
She was charged with several juvenile counts including attempted homicide, assault and illegal possession of a weapon and is in a juvenile detention centre.