A US Navy helicopter crashed this Sunday on the remote Tiwi Islands in northern Australia, killing three marines and leaving 20 seriously injured.

Five marines were transported to the Royal Darwin Hospital and, according to Northern Territory Police Commissioner Michael Murphy, everything was being done to transport all the injured to that hospital.

"Our focus as a government and as a Department of Defense is very much on incident response and making sure that all support and assistance is given at this difficult time," Australian Prime Minister Anthony Albanese said at a previously scheduled press conference in Western Australia, quoted by Reuters.

Around 2,500 people from Australia, the USA, the Philippines, Indonesia and East Timor took part in the training exercises, reports Correio da Manhã, quoting Sky News.

The US and Australia have intensified military cooperation in recent years in the face of an increasingly assertive China.