North Korea followed reportedly through on its promise to blow up tunnels used for nuclear testing on Thursday, as part of steps to reduce tensions on the Korean peninsula.
North Korea has conducted all six of its nuclear tests at the Punggye-ri site, which consists of tunnels dug beneath Mount Mantap in the northeast of the country.
The test site consists of four tunnels. The monitoring group 38 North said two unused tunnels remained.
Sky News, the only British broadcaster invited to the demolition, reported it had witnessed a “huge explosion” at the test site.
Sky’s Asia correspondent, Tom Cheshire, said he travelled 12 hours overnight in a train with blacked out windows before driving an hour in the mountains through military checkpoints to arrive at Punggye-ri.
“We hiked up into the mountains and watched the detonation from about 500 metres away.
“They counted it down - three, two, one.
“There was a huge explosion, you could feel it. Dust came at you, the heat came at you. It was extremely loud.”
A group of around 20 foreign journalists were invited on the trip, and were reportedly given a briefing by the deputy director of the North Korea Nuclear Weapons Institute who shared “unprecedented detail” of its programme, Cheshire added.
The apparent move comes ahead of a historic summit with United States, which is due to take place in Singapore on June 12.