Metro

Teen flees school after metal-detector scan yields loaded gun

A student with gang connections was found with a gun at a Brooklyn high school Thursday after a metal-detector scan.

A school safety agent found the 25-caliber pistol, with four bullets inside, while scanning backpacks at South Shore HS in Canarsie shortly after 11 a.m., police sources said.

Once the gun was ID’d, the 17-year-old fled the school, leaving his bag.

“When the agent asked, ‘What is this?’ he turned and ran out of the school,” said Derek Jackson, a union rep for the NYPD’s school safety agents.

Cops were searching for the teen Thursday. They have not named him.

A photo of the weapon (above) was obtained by The Post.

Jackson, who spoke with officers about the discovery, said the teen belongs to a gang.

The de Blasio administration intends to remove metal detectors from some of the 80 schools that use the devices, a plan that has run into opposition from the union.

“School safety saved lives at this school today because of scanning,” Jackson said. “Don’t know what was this student’s intention.”