CHICAGO (AP) — Chicago police say a 7-year-old boy was hospitalized in good condition after being grazed by a bullet when a gun accidentally discharged in a backpack at a school.

Police say the bullet struck the ground and ricocheted by the second-grader, grazing his abdomen. The incident happened at Disney Magnet Elementary School on Chicago’s North Side shortly before 10 a.m. Tuesday.

Principal Paul Riskus sent a letter to parents saying “staff immediately intervened, secured the gun, and contacted the Chicago Police Department” and the Chicago Public Schools’ Office of Safety and Security.