The United States Marine Corps and Australian authorities have confirmed the death of three U.S. Marines and serious injuries of five others following the crash of a V-22 Osprey aircraft in Australia during regular military drills.

The Melville Island crash, near Darwin off Australia’s Northern Territory coast, occurred at approximately 9:30 a.m. local time on  Sunday, as reported by the Marine Rotational Force – Darwin. The critically injured Marines were transported to the Royal Darwin Hospital for medical attention.

While the crash’s cause remains uncertain and under investigation, the Marine Corps has yet to comment on the incident.

The crashed aircraft was part of Exercise Predator’s Run, a multinational military drill involving forces from the United States, Australia, and other nations.

Australian Prime Minister Anthony Albanese described the incident as “tragic,” as per Reuters, while Northern Territory Incident Controller Matthew Hollamby labeled it as “significant,” assuring the deployment of all essential resources.