Students have returned to a New Jersey high school that prosecutors say was the target of a "Columbine-like" plot.

Police were on hand Monday morning to reassure students and parents that Bridgewater-Raritan High School is safe.

Principal James Riccobono addressed the 2,900 students before classes began Monday. The principal praised a student for alerting authorities.

Authorities say a 16-year-old junior was arrested Thursday after a police resource officer at the school was told the teen was planning an attack. Authorities say they found shotgun shells, bullets, black powder and explosives in the teen's home.

Officials also arrested the teen's 17-year-old friend, who goes to Immaculata High School.