Evans Revere, a former USA diplomat with a long history of negotiating with North Korea, said that it was evident now that talks in Pyongyang had not gone well - and that it appeared North Korea may have no intention of actually denuclearizing in the way the United States would want.
A North Korean Foreign Ministry statement called on both sides to take simultaneous actions to improve the environment surrounding the talks. State Department spokeswoman Heather Nauert said no meeting with Kim Jong-un had been planned.
"We still cherish our good faith in President Trump", the spokesman said.
Reuters reported that the talks covered methods of destroying a missile engine testing facility, as well as a general denuclearization timeline. Last week, Trump's national security adviser John Bolton said North Korea could be expected to carry out the "bulk" of denuclearisation within a year.
In the statement calling the United States stance "regrettable", the North Korean Foreign Ministry spokesman quoted by KCNA said the USA is unilaterally demanding denuclearisation and trying to postpone discussion of declaring an end to the Korean War.
The White House declined to comment on North Korea's statement to CNN.
Now, three weeks later, the two sides were still at odds on all issues, including exactly what denuclearization means and how it might be verified, after a third visit to Pyongyang by U.S. Secretary of State Mike Pompeo.
Pompeo's meeting with Japan's Minister of Foreign Affairs Taro Kono and South Korean Foreign Minister Kang Kyung-wha followed two days of talks in Pyongyang that ended on Saturday.
Not even a month ago, Trump was tweeting that the North Korea nuclear problem was all but solved, and that Americans could finally rest easy thanks to his breakthrough in talks with Kim.
Leaked US intelligence findings concluded that North Korea does not intend to give up its nuclear programme completely.
"They have gotten the U.S.to back off military exercises, back off using "CVID" [Complete, Verifiable and Irreversible Dismantlement], back off the "Libya model" of rapid denuclearization, back off on human rights, and to look the other way while China relaxes sanctions implementation".
"The US is fatally mistaken if it went to the extent of regarding that the DPRK would be compelled to accept, out of its patience, demands reflecting its gangster-like mindset", the statement said, referring to North Korea by its official initials.
"I think we made progress in every element of our discussions", he added.
It was the first time he had visited North Korea since the Donald Trump-Kim Jong-un summit in Singapore.
Mike Pompeo has shrugged off North Korea's assessment of the latest denuclearisation talks as being "gangster-like".
Before arriving in North Korea, Pompeo said he was seeking to "fill in" some details on North Korea's commitments and maintain the momentum toward implementing the agreement from the summit.
The State Department sets the record straight after reports said President Donald Trump gifted North Korean leader Kim Jong Un with a CD that included Elton John's "Rocket Man".
One hoped-for breakthrough on this trip would have been the return of the remains of US troops killed during the 1950-53 Korean War.
He admitted "there's still more work to be done" in other areas.