"The two helicopters collided during flight training. All 10 victims on board have been confirmed dead by the medical officers," Suhaimy Mohamad Suhail, senior operations commander from the fire and rescue department said.

Videos shared online showed several helicopters flying low in a formation over the Lumut naval stadium in a rehearsal ahead of the navy fleet's open day celebrations in May.

One of the choppers was seen clipping the rear rotor of another helicopter, causing both to go into a tailspin and crash.

In the footage, eyewitnesses were heard shouting "Allah, Allah, Allah".