A statement issued during worldwide negotiations with North Korea in 2005 over its nuclear weapons development said the "United States affirmed that it has no nuclear weapons on the Korean Peninsula and has no intention to attack or invade (North Korea) with nuclear or conventional weapons".
The U.S.is said to consider North Korea's declaration of halting further nuclear and missile tests as "not enough" for a "complete, verifiable, irreversible dismantlement", Yonhap said. "Thank you, a very smart and gracious gesture!" he tweeted.
But President Donald Trump, South Korean President Moon Jae-in and others have welcomed the decision, saying it's a measure of the North's sincerity in its recent outreach to the worldwide community.
The isolated Asian nation, which had already pledged to begin dismantling the nuclear test site this month, will invite journalists from China, Russia, the United States, the UK and South Korea to cover the event, KCNA said in the statement.
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.
The North also is widely believed to have as many as 60 nuclear weapons and production facilities that were not affected.
President Donald Trump applauds as U.S. detainee Kim Dong-chul gestures upon his return with Kim Hak-song and Tony Kim after they were freed by North Korea, at Joint Base Andrews in Maryland on May 10, 2018.
White House national security adviser John Bolton said on CNN's "State of the Union" on Sunday that North Korea's future could be "unbelievably strong" if it follows through on its commitment to denuclearise.
The top US diplomat did not elaborate, but his comment could refer to the type of assurances North Korea has sought in the past.
South Korea has said Kim has genuine interest in dealing away his nuclear weapons in return for economic benefits. 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.
Kim, who picked Beijing to make his maiden official trip overseas in March, has also invited Xi to visit North Korea. "The U.S. doesn't want a gradual dismantling this time, like they did in withdrawing the nuclear deal in Iran". "It means getting rid of the uranium enrichment and plutonium processing capabilities".
David Beasley said he had unprecedented access to the secretive state, telling BBC radio that North Korea's leaders had a "sense of optimism".
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.
South Korea, meanwhile, said it will hold a high-level meeting with the North Wednesday to discuss measures focusing on reducing border tensions and resuming reunions of families separated by the 1950-53 war.