A 13-year-old boy was charged Tuesday with aggravated assault, weapon offenses and related charges after he shot and wounded himself and an 11-year-old girl in a South Philadelphia home Monday night, police said.

The boy's name was not released because he was charged as a juvenile.

Police said that about 8:30 p.m. Monday, officers went to a home on the 2100 block of Etting Terrace for a report of a person with a gun. There, they found the girl suffering from a gunshot wound to her right knee. She was taken by medics to the Children's Hospital of Philadelphia, where she was in stable condition Tuesday.

Police said the boy was waving around a silver handgun when it fired. The bullet struck the boy in his left hand, then hit the girl in her right knee, police said.

The boy ran from the home, police said, and was taken by private vehicle to the Hospital of the University of Pennsylvania's emergency room, where he was in stable condition.

Neither child lived in the home, said Officer Tanya Little, a police spokeswoman. The boy is a relative of the people who live in the house, which is part of the Wilson Park public-housing development, according to the South Detective Division.

The boy and the girl, who is a friend of someone in that house, both also separately reside in the Wilson Park housing complex, South Detectives said.

Police said the gun was not recovered. They are still investigating how it got into the house and whose gun it is.