North Korea Defence Chief Hyon Yong Chol 'Executed With Anti Aircraft Guns For Falling Asleep In Meeting'

North Korean leader Kim Jong Un has reportedly executed his defence chief for falling asleep during a meeting, in a brutal killing thought to have been carried out with an anti-aircraft gun in front of hundreds of people.

South Korea's spy agency said on Wednesday that it had "credible information" that People's Armed Forces Minister Hyon Yong Chol was killed for sleeping in a meeting, and also for talking back to Kim.

A large audience reportedly watched the killing, which was carried out with a heavy duty machine gun that would "pulverise" a human body according to to Greg Scarlatoiu and Joseph Bermudez Jr from the US Committee for Human Rights in North Korea (HRNK), quoted in the Washington Post.

A man in South Korea watches a news program reporting that North Korean defence minister Hyon Yong Chol (right) was executed

Anti-aircraft guns like this one in Libya are reportedly used to execute people in North Korea

Anti-aircraft guns, usually used to shoot down and destroy planes, are extremely powerful. The killing of the country's head of defence took place at a shooting range at Kang Kon Military Academy in the capital Pyongyang in late April, according to the South Korean spy agency.

New satellite images released last month by the HRNK appear to confirm the use of the heavy weapons in the authoritarian state, which had previously been only a rumour.

They show what appears to be a firing range on the outskirts of North Korea's capital Pyongyang, with a viewing area, heavy duty anti-aircraft guns and a line of targets - people - standing about 100 feet in front of them.

The firing range close up, with people apparently lined up to be executed, although this cannot be confirmed to be what is happening

Scarlatoiu and Bermudez authored a report released with the images, and said: "A few feet behind the antiaircraft guns, there appear to be a line of troops and/or equipment... with buses and trucks at the site suggesting that people had been bused in to watch whatever was happening," The Washington Post report notes.

The authors added: "Anyone who has witnessed the damage one single US .50 caliber round does to the human body will shudder just trying to imagine a battery of 24 heavy machine guns being fired at human beings. Bodies would be nearly pulverised."

The report said the anti-aircraft guns appear to be six Soviet-made ZPU-4s - heavy weaponry first used during the Korean war in the 1950s.

Kim has repeatedly removed those in power who appear to disagree with him, and executed his uncle and chief deputy in 2013 for alleged treason.

The news of the execution was reported by South Korean National Intelligence Service officials, in a closed-door parliamentary committee meeting. According to South Korean lawmaker Shin Kyoung-min, the intelligence officials didn't say how it got the information, only that it was from a variety of channels and that it believed it to be true. The agency wouldn't comment when contacted by The Associated Press.

South Korea's spy agency has a checkered history of reliably tracking developments in North Korea, and information about the secretive state is often impossible to confirm.

Since taking power upon the death of his dictator father in late 2011, Kim has orchestrated a series of purges in apparent efforts to bolster his grip on power.

Analysts are split on whether the bloody power shifts indicate a young leader in firm control, or someone still struggling to establish himself. The most notable purge was in 2013 when Kim executed his uncle and chief deputy, Jang Song Thaek killed.

Koh Yu-hwan, a North Korea expert at Dongguk University in Seoul, said Kim Jong Un appears to be using purges to keep the military old guard in check as they pose the only plausible threats to his rule.

He said Kim could be resorting to a "reign of terror" to solidify his leadership but that would eventually have only a limited effect if he fails to produce breakthroughs in resolving the country's economic woes.

Last month, spy officials told lawmakers that North Korea executed 15 senior officials accused of challenging Kim's authority.