An 86-year-old woman was shot and injured while standing on her porch in Southwest Philadelphia late Monday night.

Police said the woman was shot in the thigh about 9:14 p.m. by a man who was firing shots as he pursued another man down 51st Street near Springfield Avenue.

"She was just an innocent bystander," Capt. Mike Ryan said at the scene. "She was just minding her own business."

An officer who arrived on the scene clamped down on the woman's wound to help stem the flow of blood. The woman, who was bleeding profusely, was in stable condition at Hospital of the University of Pennsylvania, Ryan said.

"From what I understand, the injury was serious," Ryan said.

Police described the shooter as a black male, between the ages of 16 to 20, with short hair and dressed in a black T-shirt and black shorts. He fired shots while chasing another black male, also 16 to 20, wearing a white T-shirt and tan shorts.

Investigators found three shell casings near the scene but did not yet know whether anyone else was shot, Ryan said.