Vice Foreign Minister Choe Son Hui, addressing an urgent meeting Friday of diplomats and foreign media in Pyongyang, said the North was deeply disappointed by the failure of the two sides to reach any agreements at the Hanoi summit between Kim and President Donald Trump.
He said: "We have no intention to yield to U.S. demands (at the Hanoi summit) in any form, nor are we willing to engage in negotiations of this kind".
Choe also revealed that North Korean leader Kim Jong-un would soon decide whether to restart the North's nuclear and missile development programs.
Secretary of State Mike Pompeo insisted that North Korea is keeping open the possibility of continued talks after Pyongyang's deputy foreign minister said they might walk from negotiations, criticizing the top U.S. diplomat and national security adviser John Bolton for creating "an atmosphere of hostility".
Choe said it was the US that was being too demanding and inflexible and called the demand that denuclearization come before sanctions are eased "an absurd sophism".
US Secretary of State Mike Pompeo has said he expects North Korea's leader will live up to his commitment not to resume nuclear and missile tests.
The Associated Press also reported Choe claimed, "Personal relations between the two supreme leaders are still good and the chemistry is mysteriously wonderful".
"I saw the remarks [Ms Choe] made - she left open the possibility negotiations would continue". Trump expressed to Kim that he was willing to show flexibility during a one-on-one meeting.
Mr Pompeo said Kim Jong-un had promised US President Donald Trump in Vietnam that testing would not resume. "It's the administration's desire that we continue to have conversations around this". "I'm not sure why the United States came out with this different description".
The North Korean delegation came to Hanoi with a realistic proposal of the U.S. lifting some economic sanctions as a gesture of recognition of Pyongyang's 15-month moratorium on nuclear and ballistic missile tests, Choe told diplomats and journalists. "I have every expectation that we'll be able to continue to do that", Pompeo said Friday. "They wanted the sanctions lifted in their entirety and we couldn't do that", Mr Trump told reporters.
Trump has pointed to North Korea's freeze in nuclear and missile testing since 2017 as a positive outcome from almost a year of diplomatic engagement with North Korea.
Choe issued no direct criticism of the USA president and stressed that Trump and Kim have good chemistry.
Choe's comments echoed the North's usual rhetoric at tense points in its dealings with Washington.
Moon Chung-in, South Korea's special presidential adviser for foreign affairs and national security, said if Pyongyang tries to use the reported missile activities as leverage in stalled nuclear talks, it would constitute a "bad move" that could be catastrophic.
"They're putting down a marker, saying which way things are headed if nothing changes", Pollack, of the James Martin Center for Nonproliferation Studies in Monterey, California, said.
Mr Trump and Mr Pompeo clearly stated after last month's talks that North Korean officials had asked for full sanctions relief. "It is likely to gauge the US reaction in the days ahead before making a decision to launch a rocket", he said.
"As a result, the summit ended with no significant result", the North Korean diplomat said.
Speaking of the issues regarding the DPRK, Chinese Premier Li Keqiang on Friday urged all parties to remain patient and to seize the opportunity to promote dialogue between the USA and the DPRK.
The activity at Sohae "doesn't necessarily really surprise me", Miller said.