Three crew members are still missing after a United States Marine Corps aircraft was involved in a "mishap" off Queensland's coast, but US authorities have confirmed they do not expect to find the marines alive.
Twenty-three of the MV-22 Osprey's crew were rescued in a search and rescue operation after the aircraft "entered the water" about 4pm during "regularly scheduled operations" on Saturday, according to the III Marine Expeditionary Force.
The tilt-rotor aircraft had been in Queensland as part of the Talisman Sabre joint training exercise between Australian and United States military forces, which ended on 25 July.
The exercises were taking place in Shoalwater Bay training area near Rockhampton in Central Queensland.
Defence Minister Marise Payne said no Australian Defence Force personnel were on board the aircraft.
The search for the crew members continued throughout the night but was called off this morning.
"Operations have now shifted to recovery efforts," said a statement from the III Marine Expeditionary Force (III MEF).
"The next of kin for the three missing marines have been notified."
The III MEF said recovery efforts would continue "as the sea state permits" with assistance from the Australian Defence Force.
"Recovery and salvage operations can take several months to complete," the statement read.
It said an investigation was underway and no further information was available.
MV-22 aircraft, known as Ospreys, have a somewhat chequered history, with a number of the helicopter-plane hybrids going down recently.
In December, five crew members of an Osprey had to be rescued after their craft conducted a shallow-water landing off Okinawa after a training mishap in which a rotor blade cut a refuelling hose, according to the Marine Expeditionary Force.
During a US counter-terrorism operation in Yemen, two soldiers were reportedly injured when a USMC MV-22 experienced a "hard landing" after being called in to evacuate injured troops.