Pompeo departed North Korea with a far more positive assessment, declaring that progress was made on the central issues of discussion, and downplayed North Korea's "gangster" accusation, responding by saying that "if those requests were gangster-like, the world is a gangster".
His two days of talks with senior North Korean officials had "made progress", and included a "detailed and substantive discussion about the next steps towards a fully verified and complete denuclearization, he said".
The regime's belief that the weapons are needed to deter a U.S. attack dates back almost 70 years to the still-unresolved Korean War, and will take more than a handshake to dispel.
The statement claimed the two countries' gestures of goodwill since the summit were lopsided in their significance, comparing North Korea's "irreversible step" of dismantling its nuclear test site with the American move to suspend military exercises, "which can be resumed any time at any moment".
"The United States has been clear about what we seek from North Korea to set in motion this great chain of events", Pompeo said in Hanoi.
The 1,200-word statement, attributed to an unnamed Foreign Ministry spokesman, outlined North Korean thinking at length.
While insisting again that the talks were moving forwards, he stressed that nothing had happened to merit a relaxation of the tough sanctions imposed on the North over its nuclear missile programme.
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The incident happened at an Afghan army base in Uruzgan Province in southern Afghanistan, according to a U.S. official. The force of 16,000 troops includes service members from 39 North Atlantic Treaty Organisation nations and allies.
Pompeo says sanctions would remain until Pyongyang follows through on leader Kim Jong-un's pledge to get rid of his nuclear weapons.
Pompeo said that in past two decades, US bilateral trade with Vietnam had grown 8,000 percent, and American companies had poured in billions of dollars of investments.
Just a few weeks before the Singapore summit, Trump said Chinese President Xi Jinping "could be influencing" Kim from behind the scenes shortly after Kim went to Dalian, China, for his second meeting with Xi. He said he is "hopeful" there will be a "path forward" in negotiations with North Korea. "The miracle could be yours; it can be your miracle in North Korea as well".
In his Monday tweet, Trump also raised concerns about China's commitment to denuclearization of the Korean Peninsula, suggesting it could have waned because of a trade war that has broken out between the United States and China. Lindsey Graham made on Sunday that China may be encouraging Pyongyang to push back against the deal because it is involved in a tit-for-tat trade war with the US.
Kim later said that "there are things that I have to clarify", to which Pompeo responded that "there are things that I have to clarify as well". He and the head of the North Korean negotiating team, Kim Yong Chol, cracked jokes during a working dinner, State Department spokeswoman Heather Nauert said. "The world will see continued enforcement efforts by the United States in the days and weeks ahead".
Officials from the two sides would meet next week in Panmunjom, on the border between the two Koreas, to discuss the return of the remains of roughly 7,000 US soldiers missing since the 1950-1953 Korean War. It said the US side had shown little interest, giving "certain conditions and excuses".