The incident occurred at the Lumut naval base in the western state of Perak at 9.32 a.m. on Tuesday morning (0132 GMT), the navy said.

“All victims were confirmed dead at the scene and sent to the Lumut naval base military hospital for identification,” the navy said.

A video circulating on local media showed several helicopters flying in formation, when one of the choppers’ rotor clipped another before both aircraft crashed into the ground. Local police confirmed the footage was genuine.

The navy said it would carry out an investigation into the cause of the accident.

Defence Minister Mohamed Khaled Nordin said the aircraft – a maritime operations helicopter and a Fennec military chopper – were rehearsing for a parade celebrating the 90th anniversary of the Royal Malaysian Navy, due to be held on Saturday.

Efforts were underway to verify the identities of the crew members killed, all of whom were below the age of 40, Mohamed Khaled told reporters.

(Reporting by Rozanna Latiff and Mandy Leong; Editing by John Mair and Lincoln Feast.)