3 U.S. Marines Killed, 5 Wounded and in 'Serious Condition' Following Aircraft Crash in Australia During Training

The MV-22B Osprey, tiltrotor aircraft crashed during a "routine training exercise' on Sunday

Three Marines were killed in an aircraft crash in Australia over the weekend, during what the Corps described as a "routine training exercise."

The military branch shared on Twitter that the MV-22B Osprey, tiltrotor aircraft crashed near Darwin, Australia, around 9:30 a.m. local time on Sunday.

The aircraft came down with 23 people on board "while transporting troops during a routine training exercise,” the Marine Corps said. Beyond the three casualties, five others were taken to the Royal Darwin Hospital in "serious condition."

"The Marines aboard the aircraft were flying in support of the Exercise Predators Run," a release noted. "Recovery efforts are ongoing. The cause of the incident is under investigation. Further details will be provided as the situation develops."

A public affairs officer for the Marine Rotational Force - Darwin did not immediately respond to PEOPLE's request for updates on Sunday afternoon.

Related: 3 Marines Found Dead Inside Car Parked at North Carolina Gas Station: 'Tragic Loss'

The Exercise Predators Run is expected to end on Sept. 7 and lasts 12 days, with troops from the U.S., the Philippines, East Timor, Australia and Indonesia participating in the land, sea and air exercise, per NBC News. A Marine Corps spokesperson confirmed to the outlet that all passengers onboard the aircraft were Marines.

NBC News also reports that Darwin sees a rotation of 2,500 Marines each year — with 150 currently based there.

"Our thoughts and deepest condolences are with the three U.S. service personnel who lost their lives, those who have been injured, the rest of the crew and indeed the entire United States armed forces," Australian Prime Minister Anthony Albanese wrote in a statement, adding that the Australian Defense Force was providing support, and the country will do so "as long as it is required."

Northern Territory Chief Minister Natasha Fyles and local police commissioner Michael Murphy revealed that aircraft had been sent to the site of the crash to return injured passengers, and that the "Northern Territory government stands by to offer whatever assistance is required," per NBC.

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

CNN analyst Col. Cedric Leighton told the network on Sunday that while it is too soon to determine the cause of the crash, there's "a lot of coordination that goes along with these exercises."

“The Australians are great partners, and those exercises are invaluable in providing for security in the Pacific region," he added.

Last year, five Marines died following an MV-22B Osprey aircraft crash, which was described as "an aviation mishap." CNN has also reported that Osprey aircraft crashes have happened at least 12 previous times, dating back to a 1992 crash where seven people died in Virginia.

For more People news, make sure to sign up for our newsletter!

Read the original article on People.