North Korea's Foreign Ministry said Saturday that discussions with U.S. Secretary of State Mike Pompeo were "regrettable" and it accused Washington of attempting to unilaterally force Pyongyang to scrap its nuclear weapons program.
A statement by an unnamed ministry spokesman was issued a few hours after Pompeo concluded two days of talks with Pyongyang's senior ruling party official, Kim Yong Chol, and other North Korean officials.
The statement said the outcome of the talks were "very concerning" because it initiated a "dangerous phase that might rattle our willingness for denuclearization that had been firm."
North Korea's official KCNA news agency described the talks as "extremely troubling" and cited an unnamed foreign ministry spokesperson as saying the "fastest way" to achieve a nuclear-free Korean peninsula was through a phased, bilateral approach.
U.S. Secretary of State Mike Pompeo expressed a positive view right after the talks, saying the two sides "had many hours of productive conversations" and there was "progress on almost all of the central issues."
The top U.S. diplomat said a large portion of the discussion was about a timeline for North Korea's denuclearization and a baseline declaration for its weapons of mass destruction. Pompeo did not divulge any details, but said, "We spent a good deal of time talking about each of those two things and I think we made progress in every element of our discussions."
The secretary, who is now in Tokyo, said a meeting has been scheduled for July 12 that "could move by one day or two" for conversations "between the folks responsible for the repatriation of remains" of Americans who died in the Korean War.
Pompeo did not meet with North Korean leader Kim Jong Un. State Department spokeswoman Heather Nauert said there was never any expectation of a meeting with Kim.
Pompeo began the day Saturday with a telephone call to U.S. President Donald Trump before a second day of meetings with senior North Korea ruling party official and former intelligence chief Kim Yong Chol.
As the two men gathered before their talks, Kim asked Pompeo if he slept well on his first overnight stay in the country. Pompeo confirmed he did and the two had a brief exchange before reporters were asked the leave the room.
"President Trump is committed to a brighter future for North Korea," Pompeo said.
This was Pompeo's third visit this year to North Korea and the first where he stayed overnight. It was also his first visit since President Trump met with Kim at last month's Singapore summit.
Pompeo has been charged by Trump with overseeing Kim's promise at the summit to denuclearize the Korean peninsula.
Nauert said Saturday that U.S. and North Korean officials have set up working groups to deal with "nitty gritty stuff," including validation of efforts to achieve denuclearization.
She said Pompeo had been "very firm" in the discussions in seeking three basic goals: complete denuclearization of North Korea, security assurances, and the repatriation of remains of Americans who died in the Korean War. Nauert also said progress had been made in the secretary's meetings on Friday.
WATCH: Pompeo Under Pressure to Return With Results from North Korea
Expansion by Pyongyang
Pompeo's latest trip to North Korea comes amid reports of American intelligence assessments that Kim is continuing to develop the infrastructure for his nuclear program. U.S. news accounts in recent days have shown pictures of what is said to be the expansion of nuclear-related buildings in North Korea.
Speaking Thursday aboard Air Force One on a trip to Montana, Trump said he still believes Kim will follow through on his promise and said he forged a personal connection with the leader.
"I think we understand each other. I really believe that he sees a different future for North Korea," Trump told reporters. "I hope that's true. If it's not true, then we go back to the other way, but I don't think that's going to be necessary.''
Trump's national security adviser, John Bolton, says North Korea could dismantle its nuclear arsenal within a year, but other U.S. officials have said they hope it can be accomplished by the end of Trump's first term in the White House, in January 2021.