Sky News witnesses 'spectacular' explosions on North Korea 'nuclear site'
Sky News has witnessed the demolition and closure of what North Korea says is its nuclear weapons test site in Punggye-ri.
We were present as explosive charges were detonated in the hills near Mount Mantap in the northeast of North Korea.
A number of low rise wooden buildings were also blown to complete smithereens.
Dust came at you, the heat came at you. It was extremely loud.
North Korean officials said the four tunnels that make up the underground site were now completely destroyed.
The first tunnel to be built at Punggye-ri, the eastern tunnel, was closed shortly after it was used for North Korea's first nuclear test in 2006.
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I observed and filmed what was said to be the entrance to the northern tunnel being demolished.
This tunnel was the site of North Korea's five other nuclear tests to date, starting in 2009 and including its most recent in 2017 - thought be a hydrogen bomb.
A log cabin observatory nearby was also demolished in spectacular fashion.
North Korean officials showed journalists the tunnels before they were blown.
The entrances were ostentatiously rigged with wires and bags of what we were told were plastic explosives.
The two unused tunnels, the western and southern, had remained usable, officials insisted.
Media reports suggested they may have previously collapsed.
The deputy director of North Korea's Nuclear Weapons Institute, who would not give his name and held the rank of general, told me these tunnels hadn't "suffered the slightest damage" and were "intact at this moment".
The site was still "fully prepared to conduct nuclear tests", he added.
Another officer from the institute, a colonel, said the western tunnel had been prepared for an even bigger detonation than the one carried out in September 2017, before a halt was called to nuclear testing by North Korea's leader Kim Jong Un.
The entrances to both western and southern tunnels were subsequently demolished too.
Only journalists were allowed to observe the demolition taking place; no weapons inspectors or nuclear experts were invited.
We were also prevented from taking GPS devices to the site, as well as equipment to measure radiation.
We did not observe any radiation monitors at the site.
The layout of the site did appear to match satellite images previously taken of Punggye-ri.
At a ceremony proclaiming the closure of the site later, the unnamed deputy director of the Nuclear Weapons Institute said: "The dismantling of the nuclear test ground conducted with high levels of transparency has clearly attested once again to the proactive and peace-loving efforts of the government of the DPRK being made for the peace and stability of the Korean peninsula and the world.
"The discontinuance of nuclear tests is an important process in moving towards global nuclear disarmament and we will continue to join hands with all peace-loving people in building a peaceful world, a new independent world where the dreams and ideals of humanity are realised."
Mr Kim pledged to stop nuclear testing on 20 April 2018.
