PHILADELPHIA (CBS) -- Two kids are recovering after they were shot in a South Philadelphia home last night.

Police say the gun accidentally went off when one of the kids had it in his hands.

A 13-year-old boy and an 11-year-old girl were wounded in a room at the boy's relatives house on the 2100 block of Etting Terrace in South Philadelphia.

Around 8:30 last night, police say the boy was allegedly holding and waving around the silver-colored handgun when it fired.

Police say a single shot went through the boy's hand then the girl's knee. After that, Chief Inspector Scott Small says the boy then took off.

"We did follow a trail of blood that led out the rear kitchen door."

Small says he was taken to the hospital in a private car, not ambulance, and police didn't recover the gun.

Medics took the girl to the hospital. Both are listed in stable condition.

Police say the 13-year-old is charged with Aggravated Assault, Violation Uniform Firearms Act, Simple Assault, Recklessly Endangering Another Person, and related offenses.