All 10 were crew members aboard the aircraft involved in the accident, which occurred at the Lumut naval base in the western state of Perak at 9.32am on Tuesday morning, the navy said.
“All victims were confirmed dead at the scene and sent to the Lumut army base hospital for identification,” the navy said.
A video of the incident showed one of the helicopters clipping the rotor of the other aircraft before the two crashed to the ground.
According to Malaysia’s Housing and Local Government Ministry, the two helicopters were undergoing a fly-past rehearsal for the navy’s Fleet Open Day scheduled to be held at the base in May.
The two helicopters involved were a Eurocopter AS555SN Fennec, and an Agusta-Westland AW-139.
Malaysian Defence Minister Mohamed Khaled Nordin said one of the helicopters crashed into a swimming pool while the other landed at a stadium within the military compound.
“I am going straight to Lumut to inspect the situation on the ground closely,” he said at a press conference on Tuesday.
The two aircraft, which had set off from Sitiawan field at 9.03am, crashed while training for a flyover for the 90th Naval Day celebration.
It is believed that a three-man crew was on board the Fennec helicopter while there were seven crew members in the Agusta helicopter.