A ROYAL Cambodian Armed Forces helicopter, one of a group of Z-9 helicopters received from China in 2013, has crashed during a training exercise in Phnom Penh’s Dangkor district, killing four people with one seriously injured.

Chhay Bonna, director of Phnom Penh airport, said that RCAF Air Force unit 904 was training in the area when the helicopter went down in a partially excavated field near Prey Sar prison in Dangkor district at about 9:30am. Recent rains had filled the field, giving it the appearance of a large pond.

“They conduct training every day, but there was a problem today,” he said, adding that the cause of the crash remains unclear.

Speaking to reporters at the scene this afternoon, Minister of Defence Tea Banh said there had been five people in the helicopter, with one survivor and four presumed dead.

"There's no way someone could survive this hell pond," Banh said, referring to the flooded area.

Gen. Um Phy, deputy commander in chief of the Air Forces Command, also confirmed that four people died in the incident. Among the missing was a major general, who headed the Air Force’s helicopter training unit, a brigadier general and two majors, he said.

“We have not concluded the cause of the incident and the technical experts will investigate later,” he said. “The important thing for now is bringing the bodies out of the water.”

The Z-9 helicopters cost nearly $200 million and arrived in the country last year. Some of the helicopters, which the government said were primarily intended to be used for humanitarian operations, were involved in the search for missing Malaysia Airlines flight 370 in March. ADDITIONAL REPORTING BY MAY TITTHARA