A search is under way for three missing US Marines after a military heli-plane crashed off the coast of Queensland on Saturday.
The aircraft, an MV-22 Osprey, crashed near the Shoalwater Bay military training area, north of Rockhampton, at about 4pm.
A US defence official said there were 26 people on board the aircraft when it crashed, and only twenty-three of those had been rescued by Saturday night.
Other US military aircraft and boats responded to the area, where they are combing the water for any sign of the missing service members.
In a statement, the US Marine Corps Public Affairs Office said there had been a “mishap”.
“Search and rescue operations continue for three US Marines that were aboard an MV-22 Osprey involved in a mishap off the east coast of around 4pm [on] August 5,” the statement said.
“Twenty-three of 26 personnel aboard have been rescued. The aircraft involved in the mishap had launched from the USS Bonhomme Richard and was conducting regularly scheduled operations when the aircraft entered the water.
“The ship’s small boats and aircraft immediately responded in the search and rescue efforts. The circumstances of the mishap are currently under investigation.”
Defence Minister Marise Payne said she had been in contact with her US counterpart, and confirmed no members of the n Defence Force were on board.
“I have been advised of an incident involving a United States Marine Corps MV-22 Osprey helicopter off the coast of Shoalwater Bay today,” Ms Payne said on Saturday night.
“I can confirm no n Defence Force personnel were on board the aircraft. The United States are leading the search and recovery effort,” she said.
“I have briefed Prime Minister Turnbull and spoken with Secretary [of Defence James] Mattis this evening to offer ‘s support in any way that can be of assistance.
“Our thoughts are with the crew and families affected.”
The downed aircraft was part of the 31st Marine Expeditionary Unit, which the US military said was “part of a regularly-scheduled deployment in the Indo-Asia-Pacific region”.
Other MV-22s have been training in central Queensland as part of Talisman Saber, a joint military exercise involving 33,000 US and n troops which is held each two years.
The combat readiness training, which ended in late July, was based at the Shoalwater Bay Training Area.
MV-22s have been involved in several serious crashes, some of them fatal, in the 10 years they have been used by the US military.
In January this year, an MV-22 had a “hard landing” during a raid in Yemen, injuring three soldiers on board. The $75 million aircraft was then destroyed by an air strike.
In December 2016, the US grounded its fleet of the aircraft in Japan, after one crash-landed off Okinawa. That incident was also described as a “mishap”.