Senn High School was placed on lockdown Monday morning while the school’s resource officer searched for and arrested two students with pellet guns.

The incident began about 11 a.m. at the Edgewater neighborhood school when a student went to the restroom and noticed two other students with what looked like a pistol, according to Chicago police.

That student left the restroom and immediately called his mother to report what he saw, police said. The mother called the school to alert the school’s resource officer — an employee of Chicago police.

The school’s resource officer put the school on lockdown and consulted security video to identify the armed students, police said. The officer brought two male students, 14 and 15 years old, to the office, patted them down and found a pellet gun, police said.

Another was recovered from a locker of one of the students, police said.

They were arrested and charges are pending. Police said neither of the boys had threatened anyone with the weapon.

Senn principal Mary Beck said in a robocall to parents that two students were each found “in possession of a dangerous object.”

“At no time were any students or staff in danger, and the matter is being handled according to [Chicago Public Schools] policy,” Beck said. “Again, all students and staff are safe, and we have resumed our standard operations.”

Beck said the school will continue to have extra security.