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(CNN) —  

On Sunday night in Vietnam, at a dinner with Vietnamese and American business leaders, Pompeo said Vietnam experienced an “incredible rise” over the past few decades in part due to new engagement with the United States. He then delivered a message to North Korean leader Kim Jong Un: “President Trump believes your country can replicate this path – it’s yours if you’ll seize the moment. The miracle can be yours.”

“We had many hours of productive conversations,” Pompeo told reporters Saturday in Pyongyang before boarding a flight to Tokyo. “These are complicated issues, but we’ve made progress on almost all the central issues. Some places, a great deal of progress. Other places, there’s still more work to be done.”

North Korea has said the “attitude” of the US was regrettable and not in the spirit of the June 12 summit in Singapore between President Donald Trump and North Korean leader Kim Jong Un.

“We expected the US to bring constructive measures to build confidence in accordance with the spirit of the US-NK Summit,” the statement carried by state-run news agency KCNA said.

North Korea called the outcome of the discussion “worrisome” and argued that the “cancerous issues” the US delegation raised were the same ones that had “amplified” distrust and the risk of war with past administrations, resulting in previous talks ending in failure.

The White House declined to comment on North Korea’s statement, and the State Department did not respond to requests for comment from CNN or reporters traveling with Pompeo.

Pompeo gave assurances that North Korea is still committed to dismantling its nuclear program despite satellite images that appear to show infrastructure improvements to a nuclear facility and the finalizing of a ballistic missile manufacturing site.

When asked about the satellite images possibly showing nuclear site expansions, Pompeo said, “‎We talked about what the North Koreans are continuing to do and how it’s the case we can get our arms around achieving what Chairman Kim and President Trump both agreed to, which was the complete denuclearization of North Korea.”

He added, “No one walked away from that, they’re still equally committed, Chairman Kim is still committed.”

Pompeo also told reporters that he discussed the destruction of a missile test site that Trump said was already being dismantled.

“The North Koreans also confirmed the missile engine testing facility, we talked about what the modalities would look like for the destruction of that facility as well and so some progress there as well,” Pompeo said. “And then we have laid out a path for further negotiations ‎at the working level so that the two teams can get together and continue these discussions.”

He wouldn’t share details of the discussions on a timeline for North Korea to “complete” denuclearization and a baseline declaration of weapons of mass destruction, but he said “a good deal of time” was devoting to discussing those two things.

“I think we’ve made progress in every element of our discussion,” he said, describing the conversations as “productive, good faith negotiations.”

Pompeo was able to announce a small step toward achieving another element of the agreement Trump and Kim came to during their summit last month: the repatriation of US service members remains from the Korean War.

Out of the talks, a meeting has been arranged for July 12 at the Korean demilitarized zone to discuss with North Korean officials the return of US service members remains, according to Pompeo, who said that the date could move “by one day or two.”

Although he met Friday with Kim Yong Chol, the vice chairman of the country’s Party Central Committee, Pompeo did not meet with Kim on his trip to Pyongyang.

“There will be a verification connected to the complete denuclearization, that’s what President Trump and Chairman Kim both agreed to,” he said Sunday.

CNN’s Jungeun Kim, Elise Labott, Boris Sanchez and Adam Mintzer contributed to this report.