The North Korean statement followed comments this week by top American diplomats stressing the need for Pyongyang to take additional steps toward denuclearization and contentious remarks last week by U.S. Secretary of State Mike Pompeo and North Korean Foreign Minster Ri Yong Ho on the sidelines of a regional summit in Singapore.
"As long as the U.S. denies even the basic decorum for its dialogue partner and clings to the outdated acting script which the previous administrations have all tried and failed, one can not expect any progress in the implementation" of the terms of the North Korea-U.S. joint statement, including denuclearization, a North Korean Foreign Ministry spokesperson said in an English-language statement carried by the country's official Korean Central News Agency.
The White House and State Department did not immediately return requests for comment.
The two Koreas will hold a high-level meeting Monday to review progress on implementation of the Panmunjom Declaration and discuss preparations for a possible summit, South Korea's Ministry of Unification said Thursday.
Following the landmark inter-Korean summit in April, the two held a lower-key meeting in May in Panmunjom after the U.S. abruptly canceled its planned summit with the North - which it later pulled a U-turn on.
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The North Korean government said in a statement through its mission to the United Nations that it has halted nuclear missile tests, dismantled a nuclear test site and begun to return the remains of Americans killed in the Korean War, but lamented continued criticism from USA officials.
The concessions the U.S. would offer in exchange - beyond sanctions relief or removing North Korea from the list of state sponsors of terrorism - remain unknown. But the USA has repeatedly reiterated that North Korea's complete denuclearization comes before such a goal, amid slower-than-expected progress in relevant talks.
Declaring an end to the war is the "demand of our time" and will be the "first process" toward a peace and security guarantee, the state-run "Rodong Sinmun" newspaper said. But Trump has already given Kim some concessions, including ending joint military drills with South Korea.
The Korean Peninsula is still technically in a state of war because the 1950-53 fighting ended with a ceasefire, not a peace treaty.
Trump's national security adviser, John Bolton, also said this week North Korea has not taken the necessary steps to denuclearise.
Kim and Moon met in April, at a highly publicized summit that saw the leaders hold hands and walk together across the border, and then again in a more informal summit in May.