A boy and a girl hanging out with a group of fellow students in a high school gym were shot and wounded Friday afternoon, and up to three other boys may have been involved in their shooting, police said.
One boy fled and was captured near his home, and one or two other boys were being sought, they said.
The shooting happened at the Delaware Valley Charter High School in north Philadelphia around 3 p.m. ET, authorities said.
Surveillance video shows a group of about seven students hanging around when the shooting happened, police Commissioner Charles Ramsey said. It was unclear if the shooting was accidental or intentional but it "doesn't look like an active shooter type of situation," he said.
The wounded boy and girl each were shot in an arm, but it was unclear whether one or two shots were fired, Ramsey said. The wounded students, believed to be 15 years old, were taken to a hospital near the school, where they were listed in stable condition, police said.
The boy who was captured lives kilometres away from the school in south Philadelphia and may have driven or taken a bus home after the shooting, Ramsey said. No gun was recovered, he said.
"We have not found a gun, but there's two, perhaps three, youngsters that were together," Ramsey said. "We're not sure which one fired. One of the ones that we have was part of that group. They're all boys, all students."
Ramsey didn't know what staffing or security procedures were in place at the school but said "there was a breakdown in security of some kind" because the gun got into the building.
The school was placed on lockdown and secured by SWAT officers checking each room. Students were searched and released one by one.
A spokesman for the school district didn't immediately respond to a call seeking comment. The president of the charter school's board of trustees said he didn't have any additional information about the shooting, not the only U.S. school shooting this week.
Authorities said a seventh-grader opened fire Tuesday in a New Mexico middle school gym, wounding two classmates.