Schools in Montclair, N.J. were closed Monday due to a security concern, but officials now say the threat was "neutralized."

A New Jersey teacher was arrested Monday morning for allegedly making “terroristic threats” that forced public schools in upscale Montclair to close for the day, according to police. The Montclair public school system announced the closure Monday because of what police called “a potential threat to the safety of staff members and students.

A teacher on administrative leave was arrested in Philadelphia after allegedly making online threats to another school staff member in North Jersey.