"A ceremony for dismantling the nuclear test ground is now scheduled between May 23 and 25, depending on weather conditions," it said, citing a foreign ministry press release.
The announcement confirms statements by South Korea that the North's leader Kim Jong Un had promised to shut down the site.
On Saturday the Washington Post commissioned satellite imagery of the area which appeared to show several buildings had been bulldozed.
Journalists from the United States, China, the United Kingdom, Russia and the South would be invited, KCNA added on Saturday.
The limit on foreign journalists was due to the "small space of the test ground" which it said was "located in the uninhabited deep mountain area".
The ceremony will be held just over two weeks ahead of a slated meeting between Kim Jong Un and US President Donald Trump in Singapore.
Secretary of State Mike Pompeo Friday promised the US would work to rebuild North Korea's sanctions-crippled economy if it agreed to surrender its nuclear arsenal.
"The DPRK (North Korea) will, also in the future, promote close contacts and dialogue with the neighbouring countries and the international society so as to safeguard peace and stability on the Korean peninsula and over the globe," the North Korean foreign ministry statement carried by KCNA said Saturday.
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