Police say they arrested an 18-year-old from Centereach who was carrying a BB gun on school grounds Thursday morning.

It happened around 8:30 a.m. as about 50 members of the Centereach High School football team were at practice.

Police say he approached one of the players.

"The male pulled up his shirt...this weapon, it was stuck in his waistband," says Suffolk Police Chief Stuart Cameron, "As you can imagine, this looks like a real weapon. As it turns out, this is a CO2 pellet gun."

Police say the young man left the field and started walking toward the middle school next door.

The football coach called 911, and police arrested the teen within minutes.

Authorities are withholding his name, but they say he dropped out of Centereach High School last year. He faces charges of criminal trespass and unlawful possession of a weapon on school grounds.