U.S. Secretary of State Mike Pompeo and other officials have warned against undue optimism about the North Korea-U.S. summit, saying the aim remains the "complete, verifiable, and irreversible dismantlement" of North Korea's nuclear weapons.
They insist the North must grant "unlimited" access to international inspectors.
That means North Korea must scrap not only its nuclear test site in Punggye-ri, but also its Yongbyon nuclear plant as well as any uranium-enrichment facilities. A crucial part of the process is verification, which means Pyongyang must disclose all its nuclear weapons, fissile materials, facilities, technology and researchers.
Inspectors also need to visit other facilities that are suspected of involvement in the North's nuclear weapons program.
The problem is that the international community does not have an accurate estimate of their amount or locations, so international inspectors must be granted access to any suspect facility in the North.
The International Atomic Energy Agency must be allowed to conduct inspections at any time and at any place to prevent North Korea from resuming its nuclear development.
North Korea has long been allergic to IAEA inspectors. In February 1992, North Korea agreed in a joint declaration with South Korea to forgo nuclear reprocessing and uranium-enrichment facilities. The same year it submitted to the IAEA a list of its nuclear facilities and fissile materials, but an ensuing inspection revealed that it repeatedly reprocessed fissile materials and enriched more plutonium than it admitted.
North Korea rejected requests for further inspections and kicked the IAEA inspectors out.
Drawn-out six-party talks also failed to get North Korea to agree to international inspections. In June 2008, the North blew up the cooling tower of the Yongbyon nuclear plant in a publicity stunt in front of foreign journalists but rebuffed a U.S. request for unlimited inspection of all its nuclear facilities.
North Korean leader Kim Jong-un (left) stands in front of a mobile missile launcher in an underground facility on July 14, 2017, in this screen grab from [North] Korean Central Television.