SAN DIEGO (AP) — The military says a sailor was hit by a helicopter rotor blade at Camp Pendleton Marine Corps base, north of San Diego.

The sailor was in critical condition Friday after being struck by a spinning UH-1Y Venom helicopter tail rotor blade at about 6:10 p.m. Wednesday.

The military declined to identify the sailor or release further details, saying the incident is under investigation.

The sailor was assigned to 34d Marine Aircraft Wing at Marine Corps Air Station Camp Pendleton.