Two students were shot Friday afternoon at a North Philadelphia high school.

Investigators said the shooting took place shortly before 3:30 p.m. inside the gymnasium of the Delaware Valley Charter High School, located at 5201 Old York Rd. in Logan. Two students - one male and one female - were struck once each in the arm and taken to Albert Einstein Medical Center. The victims, both aged 15, were hospitalized in stable condition. A total of seven students were inside the gym at the time of the shooting, according to officials.

A Philadelphia Police Department spokeswoman around 4 p.m. said the school was locked down and most of the students had been evacuated.  Remaining students and personnel were being let out in individual groups.

Emergency personnel set up a staging area at Old York Road and West Fisher Avenue for parents to pick up evacuated children. Parents were being asked not to report to the school.

At least one male suspect was seen fleeing the school on foot following the shooting, according to authorities. Police Commissioner Charles Ramsey said at a news conference officers tracked down one juvenile suspect, identified from school surveillance video, outside his home on the 2200 block of South Bucknell Street in Girard Park. The student was taken into custody but released Friday night after being questioned.

Ramsey said Friday the weapon was not yet recovered, and police were searching the school to see if the gun was stashed somewhere inside. The school lockdown was lifted around 6 p.m. as officers continued to comb SEPTA concourses for the firearm.

Ramsey told reporters Friday evening police were searching for two other students suspected to be involved in the shooting. One of those suspects around 7 p.m. turned himself into the Northwest Detective Division for questioning, according to police. The third suspect was still at large Friday night.

Police did not disclose which of the remaining suspects is believed to have been the gunman. "Investigators are sorting through video - slowing it down, taking a look - and conducting interviews to make sure we get everything all squared away before we say which one is actually the shooter," Lt. John Stanford said.

None of the suspects' identities were being released Friday because they are minors. It's not yet clear what led to the outbreak of violence.

Contact Alex Wigglesworth at 215-854-2305 or Follow @phila_lex on Twitter.

Contact the Breaking News Desk at 215-854-2443; Follow @phillynews on Twitter.