Two Malaysian military helicopters collided and crashed during a training session on Tuesday, killing all 10 crew onboard, the country’s rescue agency said.

“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.

Footage shared online showed several helicopters flying low in a formation over the Naval Stadium Base in Lumut in a flypast rehearsal ahead of the navy fleet’s open day celebrations in May.

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

The two helicopters involved were a Eurocopter AS555SN Fennec and an AgustaWestland AW139, the rescue agency said.