Twelve military personnel including six cadets were killed in a Brunei air force helicopter crash while flying home after jungle training, a spokesman said Saturday.
The crash occurred Friday in Kuala Belait in the oil-rich sultanate on the island of Borneo.
"We have 12 fatalities in the helicopter crash. Two military cadets survived the crash," Brunei air force spokesman Norudin Salleh told AFP.
The Brunei defence ministry said the two survivors were in stable condition.
The Bell 212 military aircraft was carrying 14 people including the pilot.
The defence ministry on its website said Sultan Hassanal Bolkiah had expressed great sadness and extended his condolences to the families of the victims.
"His majesty hoped that they would be patient, and also prayed that the souls of the victims would be blessed and placed with the pious," it said.
It also said that while the "exact circumstances of this tragic incident remain to be determined, the ministry of defence is taking appropriate action to ascertain the facts".
A local Brunei newspaper, the Borneo Bulletin, described the crash as the "worst tragedy in the history of Brunei's defence".
Despite sustaining grievous injuries, one of the two cadets who survived the crash asked: "How is my squad?", it reported.
It said one cadet was being treated for a fractured arm and an injured leg while the other underwent surgery but was in stable condition.
The national tragedy struck a day before Brunei's Muslim population marked the start of the fasting month of Ramadan on Saturday.
Britain maintains a small garrison and Bell 212 helicopter unit in Brunei and runs jungle warfare training courses for the British army.
The small oil-rich monarchy on the north coast of Borneo is surrounded by Malaysia's eastern states of Sarawak and Sabah.