Jang Song-Thaek is believed to have been killed after being found guilty of attempting to overthrow the state.
The once powerful uncle of North Korean leader Kim Jong-Un has been executed for a string of alleged crimes.
State news agency KCNA announced his death early on Friday, branding General Jang Song-Thaek a “traitor”.
Gen Jang was executed on Thursday shortly after a special military trial, the agency reported, after committing such a “hideous crime as attempting to overthrow the state by all sorts of intrigues and despicable methods with a wild ambition to grab the supreme power of our party and state”.
South Korean media said they believed he was killed by machine gun – a relatively common form of execution in the North.
The announcement came days after Pyongyang said that Gen Jang had been removed from all his posts because of allegations of corruption, drug use, gambling, womanising, generally leading a “dissolute and depraved life” and “dreaming different dreams”.
He was once considered the second most powerful official in the North.
He was seen as helping Mr Kim consolidate power after the death of his father, Kim Jong-Il, two years ago.
Gen Jang was the latest and most significant in a series of personnel reshuffles that Mr Kim conducted in an apparent effort to bolster his power.
In a viciously-worded attack, the regime accused Gen Jang of betraying the trust of both Mr Kim and his father, saying he had received “deeper trust” from the younger leader in particular.
Branding Gen Jang “despicable human scum … worse than a dog”, the regime accused him of attempting to stand in the way of Mr Kim’s succession, according to KCNA.
Gen Jang, who was married to the sister of the late Kim Jong-Il, played a key role in cementing the leadership of the inexperienced new leader.
But analysts say the 67-year-old’s power and influence had become increasingly resented by his nephew, who is aged around 30.
Gen Jang – seen as Mr Kim’s political regent and the country’s unofficial number two – had earlier been stripped of all posts and titles, with the regime accusing him of corruption and building a rival power base.
State TV this week showed photos of Gen Jang being dragged out of his seat at a meeting by two officers, in an extremely rare public humiliation of a figure who was then demonised as a drug-taking womaniser.
South Korean President Park Geun-Hye on Tuesday accused Mr Kim of resorting to extreme violence to cement his leadership.
“North Korea is now engaged in a reign of terror while carrying out a massive purge to consolidate the power of Kim Jong-Un,” she told a cabinet meeting, according to her office.
British Prime Minister David Cameron’s official spokesman said: “If this is confirmed, it is another example of the extreme brutality of the North Korean regime.”
Foreign Office spokesman said: “We are concerned at reports of the execution of Jang Song-Thaek and oppose the use of the death penalty in any and all cases worldwide. We are monitoring the situation in North Korea closely in consultation with allies.”
The White House also said the execution represented another example of the Pyongyang regime’s “extreme brutality”. The Kim family has ruled the North for six decades with an iron fist, regularly purging those showing the slightest sign of dissent. Most are executed or sent to prison camps.
Source : Sky news