An analysis Monday by the 38 North website says commercial imagery taken last week shows that several operational support buildings have been razed and rails for mining carts have apparently been removed.
The North said it plans to invite journalists from the United States, South Korea, China, Russia and Britain to inspect the process.
North Korea has begun dismantling the country's only known nuclear test site, according to satellite photos, following through on a promise made by leader Kim Jong-un ahead of his meeting with Donald Trump. However, Pyongyang has yet to say whether it will give up its nuclear weapons and dismantle related facilities other than Punggye-ri.
Xi replied that if the United States and North Korea reach a consensus on denuclearization, it would be possible to provide economic assistance to North Korea in phases.
The schedule of the June 12 U.S. "It means getting rid of the uranium enrichment and plutonium reprocessing capabilities", adding the process would also need to address North Korea's ballistic missiles. However, there are lingering doubts about whether Kim would ever agree to fully relinquish the weapons he probably views as his only guarantee of survival.
According to the KCNA announcement, the North will invite local press, but global media will be limited to journalists from China, Russia, South Korea, Britain and the United States, due to the testing ground's "small space".
The two leaders are approaching a summit on June 12 in Singapore where they are set to discuss the North's denuclearization.
The Punggye-ri site in the northeast of the country was used for all of the North's six nuclear tests and lies deep within mountains.
Sen. Lindsey Graham of SC said on CBS' "Face the Nation" Sunday that he thinks Congress would be willing to economically support North Korea once they get rid of their nuclear weapons, and stop trying to develop them.
Pompeo said the U.S. would not be willing to invest taxpayer dollars to help the country, but was willing to "lift sanctions" to pave the way for private American investment in North Korea's energy, agriculture and infrastructure sectors. In June 2008, global broadcasters were allowed to show the demolishing of a cooling tower at the Nyongbyon reactor site, a year after the North reached an agreement with the US and four other nations to disable its nuclear facilities in return for an aid package worth about $400 million.