SEOUL (AFP) - Two young soldiers in South Korea's special warfare unit died during training, the military said on Wednesday, following a series of incidents and suicides that have unleashed public fury over bullying in the army.

The two staff sergeants in their early 20s, surnamed Lee and Cho, died after collapsing during training on Tuesday night, a Defence Ministry spokesman said. They appeared to have suffocated during a mock training exercise on how to survive when captured by enemies, said a spokesman of the Special Warfare Command (SWC). "They had breathing problems during the mock captivity training when their heads were wrapped in cloth, and died after being sent to hospital," the spokesman Lee Hong Joo said.

Another soldier is being treated after being injured during the training, he said without elaborating further.

During the drill, soldiers had to spend an hour kneeling down with their heads wrapped in cloth and hands bound behind the back, military officials said. "This is the first time that we adopted the programme, which has been used by special warfare units in the US, Britain and Australia," it quoted one official at the SWC.

"There must have been some sloppiness in carrying out the training," said another official quoted by Yonhap.

The latest incident comes as the army faces widespread public fury over a series of deaths and suicides of young conscripts caused by barrack-room bullying.

South Korea's army chief of staff Kwon Oh Seong resigned last month to take responsibility for the death in April of a bullied soldier.

The 23-year-old private, surnamed Yoon, died of asphyxiation after being struck in the chest by comrades during mealtime, with a chunk of food lodged in his airway.

Five young soldiers were later arrested for manslaughter after an initial investigation showed Yoon had been repeatedly bullied.

The case - revealed by rights activists in July - came on the back of two separate suicides by army privates also in July, and a deadly shooting spree in June in which a sergeant shot dead five comrades for taunting him.

Conscripts, most of them in their early 20s, account for the lion's share of the military's 690,000 active personnel.