Pompeo said in Tokyo there was still a lot of work to do, but he was confident North Korean leader Kim Jong Un would stick to a commitment to abandon nuclear weapons he made during a summit with U.S. President Donald Trump in Singapore last month.
Republican Senator Lindsey Graham said on Sunday that the setback in talks between the United States and North Korea could be blamed on China. He left with a harsh reminder that the North Korean leader expects something in return.
Before leaving Pyongyang, Pompeo told reporters that his conversations with senior North Korean official Kim Yong-chol had been productive, conducted in good faith and that a great deal of progress had been made in some areas.
"The U.S. still believes North Korea will denuclearize substantially before we give them any major rewards, while North Korea believes that the two need to move together jointly, and both make concessions".
"The U.S. side never mentioned the issue of establishing a peace regime on the Korean Peninsula, which is essential for defusing tension and preventing a war", an unidentified foreign ministry spokesman said.
Mr Pompeo said that in past two decades, U.S. bilateral trade with Vietnam had grown 8,000 per cent, and American companies had poured in billions of dollars of investments.
The North pushed for a phased approach with a incremental dismantling of its nuclear program accompanied by the USA gradually easing sanctions and providing other incentives.
Pompeo said the two sides agreed to hold discussions on July 12 on the repatriation of remains of Americans killed in the 1950-53 Korean War, and also discussed "modalities" for the destruction of a missile engine testing facility.
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The US politician did not meet with North Korea's leader during this visit.
"The road ahead will be hard and challenging and we know critics will try to minimize the work that we have achieved", he said. He said: "I'm counting on Chairman Kim to be determined to follow through on the commitment that he made".
When Kim added Pompeo "might not have slept well last night" following Friday's discussions, the top US diplomat said he "slept just fine" and that he agreed the two sides "did have a good set of conversations".
North Korea's statement bashed hopes for a quick deal and is sure to fuel growing skepticism in the US over how serious Kim is about giving up his nuclear arsenal.
Today's meeting follows three hours of talks at the Baekhwawon state guest house in Pyongyang on Friday, following the USA delegation's arrival in Pyongyang just before noon. The ministry said Mr. Kim had written a personal letter to Mr. Trump, reiterating that trust.
President Donald Trump was accused of forcing the North Korea summit "for headlines" by MSNBC host Joe Scarborough.
Pompeo wrapped up two days of talks in the North Korean capital on Saturday on an optimistic note even without meeting Kim Jong Un, as he had on his previous two trips. "But expectation and hope of ours were so naive as to be foolish", read the statement.
"So the work that we do, the path toward complete denuclearization, building a relationship between our two countries, is vital for a brighter North Korea and the success that our two presidents demand of us", he added.
The criticism, published on North Korea's government-run Uriminzokkiri website, said Washington should stop provoking the North with an "anachronistic human rights racket' at a time of diplomatic attempts to improve ties".