A Long Island high school and middle school were locked down Tuesday morning after reports of gunfire, officials said.

Police on scene in Roosevelt told reporters a man had fired off three gunshots on the football field at Roosevelt High School after arguing with landscapers over downed trees, according to ABC7.

The man, whose name was not released, was in custody, according to the outlet.

The shots were reported just after 9 a.m., according to Nassau County police, who were on the scene for an “active investigation.”

Nearby Roosevelt Middle School was also placed on lockdown.

“The High School and Middle School are on lockout due to an incident in the area. Everyone is safe and secure. Please do not approach the surrounding areas. Police have the area secure,” the school posted online.

County police did not release any additional information.

Students had yet to return for the new year, which starts Sept. 3, but teachers and staff were inside preparing for the fall semester, school officials told The Post.