US Secretary of State Mike Pompeo says he remains "hopeful" that Washington can continue to negotiate with North Korea, downplaying an apparent threat from Pyongyang to end the talks.
He said that Kim Jong Un at a recent summit in Hanoi had promised not to resume nuclear testing.
"We have every expectation he will live up to that commitment," Pompeo said in Washington on Friday. "We're hopeful that we can continue to have conversations, negotiations."
He was speaking hours after reports emerged quoting a senior North Korean diplomat as threatening to break off further denuclearisation talks with the United States.
"We have no intention to yield to the US demands in any form, nor are we willing to engage in negotiations of this kind," deputy foreign minister Choe Son Hui was quoted as telling a press conference in Pyongyang.
US President Donald Trump's summit with North Korean leader Kim last month in Vietnam ended without any progress, with the US president walking out of talks.
The US side has said they are not prepared to offer North Korea the sanctions relief Pyongyang is demanding without progress on denuclearisation.
The talks broke down because the US side was "too busy pursuing their own political interests and had no sincere intention to achieve a result," Choe said in comments carried by Russian state news agency TASS.
Russia and China, which border North Korea, have the relatively closest diplomatic relations with the insular North Korean state.
During the summit in Vietnam, Pompeo and US National Security Adviser John Bolton created an "atmosphere of hostility and mistrust," Choe was quoted as saying.
That atmosphere "obstructed" Trump and Kim's "constructive effort for negotiations," the diplomat was quoted as saying.