The surprise declaration, which came in a pre-dawn dispatch in North Korea's state media, appears to cool what had been an unusual flurry of outreach from a country that past year conducted a provocative series of weapons tests that had many fearing the region was on the edge of war.
The shutdown process will unfold under the presences of journalists, including those from the US and South Korea.
Specifically, it is not being revealed whether the International Atomic Energy Agency (IAEA) will lead inspections of North Korea's nuclear facilities or whether it would involve the permanent five, or P5, members of the UN Security Council - China, France, Russia, the United Kingdom and the United States, along with South Korea.
Ahead of the April 27 inter-Korean summit, NGA published a separate assessment that North Korea had started dismantling significant components and structures associated with nuclear test observation at Punggye-ri.
The North did not reveal the number of spots it would give to non-Korean journalists, the ministry said.
Satellite imagery shows North Korea has started dismantling its only known underground nuclear test site in line with an announcement the country made last month, a US institute monitoring the North said Monday.
North Korea has announced that it will dismantle its nuclear test site.
Roh Jae-cheon, spokesman for South Korea's Joint Chiefs of Staff, said the South's military has seen signs that the North is conducting "preparatory work" so that it can carry out its plans to shut down the testing ground.
US President Donald Trump and North Korean leader Kim Jong-un will meet on 12 June, a scenario that seemed improbable given the insults and threats exchanged between the two leaders in the past year.
North Korea has agreed to send two of its diplomats to an global forum hosted by South Korea's unification ministry in Kazakhstan this week.
U.S. Secretary of State Mike Pompeo said in a TV interview on Sunday that if North Korea agrees to denuclearize, "of course there will be sanctions relief". USA intelligence assessments suggest that much of the latter work will have been completed prior to the arrival of foreign observers.
Still, the closure of the underground testing site could be a useful precedent for Washington and Seoul as they proceed with the nuclear negotiations with Pyongyang, analysts say.
If the dismantling occurs at the end of the month, it will not be the first time North Korea has publicly destroyed a nuclear facility. Thus, motivated by what might have happened, China behind the scenes has brought about the meetings between North and South Korea and between Trump and Kim. It is highly likely that the North would respond positively if the US President and his allies come out with an incentives package to address North Korea concerns.
"I think they're hopeful".
The Koreas are due to hold high-level talks in the peace village of Panmunjom on the southern side of the demilitarised zone (DMZ) dividing them on Wednesday.
"People who can verify North Korea has truly given up nuclear weapons must go", Kono said.