Transcript for Trump, North Koreans clash after summit fizzles

fallout from that collapsed nuclear summit with North Korea, this morning there is a new war of words after president trump walked away from the talks. The north Koreans are now disputing his version of what happened in Vietnam. Our Terry Moran has more from the white house and, Terry, the north Koreans say Kim Jong-un might be done negotiating with the U.S. Reporter: Well, that's the threat they've issued, Cecilia, good morning, but state run media in North Korea is already toning that down a bit so could be posturing. President trump had such high hopes for the Vietnam summit but at the end of the day, what happens was pretty normal. The two sides couldn't agree so the president walked away from a deal he didn't like and now it's back to square one. Overnight president trump back home in the white house earlier than expected after his second summit with north Korean dictator Kim Jong-un came to an abrupt end. We didn't sign anything today. It didn't quite work out. I would say that I wasn't satisfied and perhaps he wasn't Reporter: The real sticking point, trump explained, sanctions. Kim Jong-un demanding that all sanctions on his country must be lifted in exchange for him dismantling North Korea's largest nuclear facility but no promise of ending the rest of his extensive nuclear and missile program. I didn't want to give up the sanctions unless we had a real program and they're not ready for that and I understand that fully but I wanted them to denuke. Reporter: Hours after talking ended, a historic first, north Korean officials held a press conference to push back. Reporter: They claim they only asked for some of the sanctions to be lifted, not all. Trump's warm relationship with Kim is the cornerstone of this nuclear diplomacy in Korea and that says potential democratic rival Joe Biden is the real problem. The president treats everything like it's a real estate deal. I'm not being a wise guy. Just let me in the room, I can convince the other party to make a deal. Well, it requires hard, hard, hard and consistent diplomacy. Reporter: As you see Democrats are sure to make the president's Korea diplomacy and his bromance with Kim Jong-un, one of the world's worst dictators, an election issue but the real question is will Kim resume testing nuclear weapons and ballistic missiles and if he does, how will president trump respond? That is the question. Okay, Terry, thank you. Democrats might be seeing this as a fighting issue but Republican, you know, George, are largely calling what happened in Vietnam a job well Right of him to walk away and I'll ask the secretary of state Mike Pompeo about this on Sunday on "This week."

This transcript has been automatically generated and may not be 100% accurate.