This comes after students brought knives to school on several occasions, including to a school dance last month.
No one was hurt in that incident, but one student was charged with making threats.
Interim Superintendent Thomas Baruffi said the district is enforcing a long-standing policy.
"This is a safe school district with great kids, but we all need to take precautionary measures from time to time to maintain that safety," he said in a statement.
He also said the district is looking into using a real-time notification app for students to report safety concerns.