On Sunday, a “tragic” event involving a US military plane happened in northern Australia during military exercises, Prime Minister Anthony Albanese said, adding that his government was focused on offering assistance.

According to Sky News Australia, a v-22 Osprey chopper carrying roughly 20 US Marines crashed off the coast of Darwin. According to the Australian Broadcasting Corporation (ABC), one person is in critical condition, two are stable, and no fatalities have been reported.

During a previously arranged news conference, Albanese declined to offer specifics on the accident or rescue efforts, which he said occurred on Melville Island north of Darwin during Exercise Predator’s Run 2023.

“Our focus as a government and as a department of defense is very much on incident response and on making sure that every support and assistance is given at this difficult time,” he said.

Australian personnel were not involved, Albanese said.

Northern Territory Police were responding to reports of an aircraft crash on Melville Island, the fire and emergency services said in an emailed statement.

The U.S. Defense Department was aware of media reports about the crash “but we do not have anything we can provide at this time”, a duty officer said in an emailed statement.

The U.S. and Australia, a key ally in the Pacific, have been stepping up military cooperation in recent years in the face of an increasingly assertive China.

Four Australian soldiers were killed last month during large bilateral exercises when their helicopter crashed into the ocean off the coast of Queensland.