CHICAGO – Two teens playing with a 9 mm handgun inside a Chicago classroom both ended up shot in the leg after a bullet discharged as they were passing the gun between them, police said.

The boys were sitting in the back of a science classroom at the Chicago Vocational Career Academy on the city’s South Side at about 2:15 p.m. The gun discharged as one boy passed the gun to the other, striking the second boy in the thigh and the other near the knee, said Robert Lopez, an assistant deputy police superintendent.

Lopez said the boys were both 15 years old, but police and school reports listed the boy who brought the gun to school as 15 and the other as 14.

The Chicago Fire Department transported the teens to local hospitals in “critical/serious” condition, spokeswoman Eve Rodriguez said. Police spokesman Tom Polick initially said both students were in good condition.

The teen who brought the gun to school panicked, ran outside the building and dumped the gun near the front of the building, Lopez said. A Chicago police officer assigned to the school confronted the student as he re-entered the building, and the student led him to the gun, police said.

There was conflicting information about whether all students at the school are required to pass through the building’s metal detectors.

Lopez said students are chosen at random to go through the detectors because it would take too long to scan each teen.

But Michael Vaughn, a spokesman for Chicago Public Schools, said all students are required to go through metal detectors every day.

School administrators indicated the teen who brought the gun to school arrived later in the school day, Vaughn said. But all students who enter the building at any time are required to be screened, Vaughn said.

School officials planned to interview the students involved and review footage from the school’s extensive surveillance camera system, he said.

“How the weapon got into the building obviously is a main concern for us,” Vaughn said, adding that additional security measures would be used to help screen students at the building’s entrances.

Lopez said there would be charges against the teen who brought the gun to school, but he had no details.

It was the second shooting on school property in less than a month. On March 22, two students standing in the parking lot were shot and wounded after a car pulled into the lot and an occupant opened fire, Bond said.

The students both recovered from their wounds, but no arrests were made, Bond said.

The academy, which opened in 1940, has about 2,000 students in grades 9 through 12. Students enter a three-year vocational career path in their sophomore year, including “majors” such as accounting, cosmetology, graphic arts and carpentry, according to the school’s Web site.

The most recent school-related fatal shooting of a student in the Chicago area occurred in 2003 when 16-year-old Kenneth Porter was shot a few blocks from Proviso East High School in suburban Maywood, according to the National School Safety Center.