It happened Metropolitan High School in the Longwood section around 3 p.m.
Police responded to the call at 3:20 p.m. They found a bullet hole in the floor of a classroom inside the school.
A 17-year-old is in custody, officials said. He is being questioned at the 41st Precinct.
No injuries were reported.
The NYC Department of Education issued this statement about the shooting:
"Students and staff are safe and this troubling incident is being investigated. We are treating this with the utmost seriousness and are working with the NYPD to ensure swift follow-up action is taken."
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