Nassau police responded to a report of shots fired during a Baldwin High School homecoming football game Friday night against Hicksville High School, police said.
No one was hit by gunshots, police said, but officers found a teenager with a stab wound.
The teenager was taken to a hospital for treatment of a non-life threatening injury, police said.
Christina Schmohl, a Baldwin School district spokeswoman said, "We did have an incident that did occur and we've involved the police and they are investigating. Until they've completed that investigation we cannot comment further."
But Schmohl said the football game, that began about 7 p.m., was suspended at 8:30 p.m., when shots were heard coming from the school parking lot.
School security and police at the game immediately asked everyone to leave the area, Schmohl said. The evacuation was orderly, Schmohl said.
An area to the rear of the high school was closed off by police Friday night as part of their investigation.
No information was immediately available as to whether that investigation would affect classes Monday.