SEOUL, South Korea -- High-level talks between the United States and North Korea appeared to hit a snag on Saturday as Pyongyang said a visit by U.S. Secretary of State Mike Pompeo had been "regrettable" and accused Washington of making "gangster-like" demands to pressure the country into abandoning its nuclear weapons.

The statement by an unnamed North Korean Foreign Ministry spokesman on Saturday came after Pompeo concluded two days of talks with North Korean officials led by top North Korean negotiator Kim Yong Chol. Pompeo left North Korea without meeting directly with North Korean leader Kim Jong Un, as he has during previous visits.

The statement said the U.S. betrayed the spirit of last month's summit between President Trump and Kim Jong Un by making unilateral demands on "CVID," or the complete, verifiable and irreversible denuclearization of North Korea. It called the outcome of the follow-up talks "very concerning" because it has led to a "dangerous phase that might rattle our willingness for denuclearization that had been firm."

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"We had expected that the U.S. side would offer constructive measures that would help build trust based on the spirit of the leaders' summit ... we were also thinking about providing reciprocal measures," an unnamed spokesman of Pyongyang's Foreign Ministry said in a statement carried by the North's official Korean Central News Agency.

"However, the attitude and stance the United States showed in the first high-level meeting (between the countries) was no doubt regrettable," the spokesman said.

In criticizing the talks with Pompeo, however, the North carefully avoided attacking Mr. Trump, saying "we wholly maintain our trust toward President Trump," but also that Washington must not allow "headwinds" against the "wills of the leaders."

The lack of a meeting with Kim, and North Korea's description of the talks, raise concerns about the future of denuclearization. After the Singapore summit, Mr. Trump said North Korea no longer poses a nuclear threat.

Just landed - a long trip, but everybody can now feel much safer than the day I took office. There is no longer a Nuclear Threat from North Korea. Meeting with Kim Jong Un was an interesting and very positive experience. North Korea has great potential for the future! — Donald J. Trump (@realDonaldTrump) June 13, 2018

But Pompeo on Saturday did not directly answer some questions from reporters about how that process is going, after NBC News reported that North Korea is expanding some nuclear test sites. When a reporter asked Pompeo if he brought up satellite images seeming to suggest some nuclear facilities are expanding, the Secretary of State said North Korea and the U.S. are "equally committed" to denuclearization.

"Well, your characterization is interesting. ‎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," Pompeo told reporters. "There's no -- no one walked away from that, they're still equally committed, Chairman Kim is still committed. I had a chance to speak to President Trump this morning, I know my counterpart spoke with Chairman Kim during the course of our negotiations as well. We had productive, good-faith negotiations."

Pompeo said "progress" made in Pyongyang, although he did not offer a timeline for denuclearization.

"I'm not going to get into the details of our conversations, but we spent a good deal of our time talking about each of those two things, and I think we made progress in every element of our discussion," Pompeo told reporters.