CHICAGO (CBS) — A grenade caused a scare Monday morning at Oscar Mayer Elementary School in the Lincoln Park neighborhood, but it turned out to be a fake.

Police were sent to the public school, at 2250 N. Clifton Ave., for reports of a suspicious object sometime before 8:30 a.m.

What was suspected to be a live grenade was found at the school. Classes were not yet in session at the time, but students could not enter their classrooms as police went in.

But it turned out that the grenade was a replica, and students were sent to their classrooms, Chicago Public Schools officials said.

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