North Korea has reportedly begun to dismantle a key nuclear test site just weeks before ruler Kim Jong-un is due to meet President Donald Trump for a historic summit.

Satellite images examined by American researchers appear to show building demolitions, removal of railways, and overturned mining carts at the Punggye-ri nuclear test site in North Korea.

The researchers are relying on commercial satellite imagery from May 7, according to the 38 North web site.

The site analyzed images which show significant changes that have been made at the location which are consistent with decommissioning.

'Between April 20 and May 7, 2018, the probable engineering office building and a possible instrumentation shed located just outside the North Portal (where the last five underground nuclear tests have been conducted) were razed along with at least two smaller buildings or sheds,' according to 38 North.

‹ Slide me › Satellite images examined by American researchers appear to show building demolitions, removal of railways, and overturned mining carts at the Punggye-ri nuclear test site in North Korea

‹ Slide me › The site analyzed images which show significant changes that have been made at the location which are consistent with decommissioning

‹ Slide me › The above before-and-after images show the removal of rail lines, buildings, and sheds

‹ Slide me › The above before-and-after image shows an office building removed, a building roof partially removed, and other facilities that were taken down

‹ Slide me › The above images show the main administrative support area, which has been largely left intact

‹ Slide me › The above images show how a number of structures in the command center have been taken down

One large truck is observed on the access road from the tunnel area to the Command Center

No personnel or significant activity is observed at the barracks area

North Korea had previously scheduled the dismantlement of Punggye-ri for sometime between May 23 and 25 in order to uphold its pledge to discontinue nuclear tests, the country's state media reported on Saturday a month ahead of the historic summit

The Punggye-ri site inside Mt Mantap in North Korea has been subjected to five different bombs. Political enigma and North Korean ruler Kim Jong-un announced the decommissioning of Punggye-ri earlier this year

'Part of the roof was removed from the probable compressor building that evidently provided ventilation to the tunnel system under Mt. Mantap.

'A possible air line, which connected that building to the North Portal, may have also been removed.'

North Korea had previously scheduled the dismantlement of Punggye-ri for sometime between May 23 and 25 in order to uphold its pledge to discontinue nuclear tests, the country's state media reported on Saturday a month ahead of the historic summit.

The official Korean Central New Agency said dismantlement of the Punggye-ri nuclear test ground would involve collapsing all of its tunnels with explosions, blocking its entrances, and removing all observation facilities, research buildings and security posts.

Kim Jong-un, right, met with US Secretary of State Mike Pompeo, left, ahead of his planned nuclear summit with Donald Trump in Singapore next month

'The Nuclear Weapon Institute and other concerned institutions are taking technical measures for dismantling the northern nuclear test ground ... in order to ensure transparency of discontinuance of the nuclear test,' KCNA said.

Trump and Kim will hold talks in Singapore on June 12, the first-ever meeting between a sitting U.S. president and a North Korean leader.

Trump's Secretary of State Mike Pompeo said on Friday that North Korea can look forward to 'a future brimming with peace and prosperity' if it agrees to quickly give up its nuclear weapons.

Trump welcomed the North Korean announcement.

'North Korea has announced that they will dismantle Nuclear Test Site this month, ahead of the big Summit Meeting on June 12th,' he tweeted. 'Thank you, a very smart and gracious gesture! Thank you, a very smart and gracious gesture!'

South Korea's presidential office echoed the sentiment on Sunday, saying it shows Pyongyang's willingness to denuclearize through actions beyond words.

However, in spite of its pledge to stop testing, North Korea has given no indication it is willing to go beyond statements of broad conceptual support for denuclearization by unilaterally abandoning a nuclear weapons program its ruling family has seen as crucial to its survival.

Did Kim promise to end missile launches because his test site was ALREADY out of action? Kim Jong-un only agreed to freeze his missile tests because his underground nuclear test site has collapsed, Chinese experts suggested. The dictator announced on Saturday he would halt nuke trials and intercontinental missile launches and also vowed to dismantle the atomic facility at Punggye-ri in the country's north east to 'transparently guarantee' the end of testing. But the surprise announcement comes after reports last year of major earthquakes and landslides in the mountainous area in the wake of five test blasts carried out by the secretive state in recent years. The dictator announced on Saturday he would halt nuke trials and intercontinental missile launches. But doubt now surrounds the honesty of this claim after evidence revealed the test site was already damaged, including by landslides depicted on this map According to the South China Morning Post, two groups of Chinese experts say the military facility has collapsed 'putting China and other nearby nations at unprecedented risk of radioactive exposure'. One of the experts said this could be the real reason behind Kim Jong-un's decision to end his missile and nuclear trials. The tyrant had claimed that the freeze was because he had now successfully developed the country's arsenal, including miniaturizing warheads to fit them on to rockets. But Wen Lianxing, from the University of Science and Technology of China in Hefei, and his researchers have concluded that a major collapse took place at Kim's atomic site after the country's sixth nuclear test in September. At the time, Japan estimated that the blast was measured at 120 kilotons, eight times the size of the US device that destroyed Hiroshima in 1945. Satellite images appeared to show multiple landslides in the wake of the hydrogen bomb blast, with green mountains reduced to muddy hillsides. Weeks later, unverified reports emerged that up to 200 workers may have been killed during the construction of a new tunnel at the site. Three small earthquakes then hit nearby regions, it is claimed. A map showing the atomic facility at Punggye-ri and piles of dumped material that show the construction of a tunnel, where dozens of workers are thought to have died after the structure collapsed Advertisement

In announcing the plan to shut Punggye-ri last month, Kim said North Korea no longer needed to conduct tests because it had completed its goal of developing nuclear weapons.

KCNA said journalists, including from the United States and South Korea, would be invited to cover the event, to 'show in a transparent manner the dismantlement of the northern nuclear test ground to be carried out'. The exact date of the closure will depend on weather conditions, the agency said.

To accommodate the traveling journalists, North Korea said various measures would be taken including 'opening territorial air space'.

South Korean officials said in April that North Korea also planned to invite experts from the United States and South Korea for the Punggye-ri shutdown, but KCNA made no mention of this.

Last month, South Korean President Moon Jae-in had asked the United Nations to help verify the shutdown.

South Korea's deputy nuclear envoy Jeong Yeon-doo will visit the International Atomic Energy Agency (IAEA) in Vienna this week to discuss the 'complete denuclearization of North Korea' the foreign ministry said on Sunday.

Donald Trump and Melania welcomed three Americans imprisoned in North Korea back to America to cheers and applause last week

All of North Korea's six known nuclear bomb tests have taken place at Punggye-ri, in the northeastern of North Korea where a system of tunnels have been dug under Mount Mantap.

According to Chinese academic reports, North Korea's most recent nuclear test in September of what Pyongyang said was a hydrogen bomb, was so large it triggered a collapse inside the mountain, rendering the entire site unusable for future tests.

But U.S. intelligence officials have said it remains usable and could be reactivated 'in a relatively short period of time' if it was closed.

Jeffrey Lewis, director of the East Asia Nonproliferation Program at California's Middlebury Institute of International Studies, said in a blog post this week that recent satellite images had shown the removal of some buildings from the site.

On Saturday, he told Reuters that closure of Punggye-ri did not mean much in terms of disarmament, given that the United States, for example, stopped nuclear testing in 1992.

'It would, however, require North Korea to clear out the test tunnels and rebuild any infrastructure that might be removed — or dig new tunnels at the site or elsewhere. So, it's a good confidence building measure, but not necessarily a sign of irreversible disarmament.'