Union County Magnet High School was under lockdown Friday afternoon.

A heavy police presence and parents rushing to get their children were seen on the campus.

The cause of the lockdown is unknown.

Students say the lockdown started at around 1:15 p.m. and lasted for a few hours.

A student's father says he was notified of the lockdown shortly after it happened, and that there wasn't a sense of urgency hours after.

News 12 New Jersey reached out to the County Sheriff's Office and the County Prosecutor's Office.