MC2 Adam D. Wainwright / U.S. Navy
The aircraft had launched from the USS Bonhomme Richard (LHD 6) and was conducting regularly-scheduled operations when it crashed into the waters.
Vessels and aircraft from the 31st Marine Expeditionary Unit and the Bonhomme Richard Expeditionary Strike Group immediately responded and were taking part in the rescue operation.
The aircraft was described as a MV-22 and was assigned to the Marine Medium Tiltrotor Squadron 265 of the 31st Marine Expeditionary Unit.
Australian Defense Minister Marise Payne said no Australian defense force personnel were on board the aircraft.
She added that Australian Prime Minister Malcolm Turnbull had been briefed on the situation and had spoken with U.S. Secretary of Defense James Mattis.
No further details were immediately available.
President Donald Trump was briefed Saturday morning on the crash by his chief of staff, John Kelly.
CORRECTION (Aug. 5, 2017, 2:19 a.m.): An earlier version of this article misstated the type of crashed aircraft. It is a U.S. Marines aircraft, not an Army aircraft.