North Korea is preparing several of its nuclear and missile test sites for international inspections, South Korean news agency Yonhap reported Wednesday.

Kim Min-ki of the ruling Democratic Party said South Korea’s National Intelligence Service observed intelligence activities that seemed to be in preparation for "possible visit by outside experts" at Punggye-ri nuclear test site and the Sohae satellite launching ground. However, no major movements were seen at Yongbyon nuclear complex.

Though North Korea has stopped nuclear and missile tests in the past year, it drew criticism for not allowing international inspections of its dismantling of Punggye-ri nuclear site in May.

In September, South Korean President Moon Jae-in said North's leader Kim Jong Un had pledged to close Sohae satellite launching ground and also allow international inspectors to observe a "permanent dismantlement" of key missile facilities.

This was in response to Washington’s demands that Pyongyang should take steps to fully close the nuclear and missile facilities before it agrees to North’s call for an official end to the Korean War and easing of international sanctions.

Earlier this month, U.S. Secretary of State Mike Pompeo met the North Korean leader during which the latter agreed to allow foreign inspectors to see the country’s Punggye-ri nuclear test site.

“There’s a lot of logistics that will be required to execute that, but when we get them, we’ll put them on the ground,” Pompeo said.

He added the “real progress” in the denuclearization talks would come at a second summit between Kim and President Donald Trump.

“Both the leaders believe there’s real progress that can be made, substantive progress that can be made at the next summit. And so we’re going to get (that meeting) at a time that works for each of the two leaders in a place that works for both of them. We’re not quite there yet, but we’ll get there,” Pompeo had said.

In August, North Korea had threatened to stall the denuclearization process as it accused the U.S. of pushing for international sanctions and making baseless allegations despite Pyongyang’s goodwill moves.

"As long as the U.S. denies even the basic decorum for its dialogue partner and clings to the outdated acting script which the previous administrations have all tried and failed, one cannot expect any progress in the implementation,” a North Korean foreign ministry spokesperson said in a statement at the time.

It also accused Washington of “making baseless allegations against us and making desperate attempts at intensifying the international sanctions and pressure” and "insulting the dialogue partner and throwing cold water over our sincere efforts for building confidence which can be seen as a precondition for implementing” the agreement between Kim and Trump.

North Korea said it was still willing to implement the agreement made at the historic June 12 summit between the two leaders, during which they signed an agreement committing to work together to “build a lasting and stable peace regime on the Korean Peninsula.”