A 12-year-old boy was arrested on Monday at an Orlando middle school after a security official found two weapons in his backpack. The weapons included a fully loaded MAC-10 machine pistol, similar to the one pictured in this file photo. (QMI Agency files)

A 12-year-old boy was arrested on Monday at an Orlando, Florida, middle school after a security official found two weapons, including a fully loaded MAC-10 machine pistol, in his backpack, a police official said.

Authorities examined the 7th-grader’s bag after receiving a tip that a student brought a gun to the Glenridge Middle School, said Orlando Police Department spokesman Sergeant Jim Young.

Police said a preliminary investigation found the boy did not intend to harm any students. The other weapon was a handgun, Young said.

The student was arrested on a charge of possession of a firearm on school property and taken to a local juvenile detention centre.

A former student of the University of Central Florida, also in Orlando, shot and killed himself early on Monday in a dormitory apartment where police found guns, bombs and writings suggesting he had been planning a campus attack, authorities said.

The dormitory was evacuated and classes were canceled on Monday morning, but resumed at midday after the explosives were removed.