Transcript for Trump, Kim meeting in Vietnam cut short

No deal on North Korea's nukes so the president cut the summit short, there you see him leaving Vietnam early this morning. After the talks collapsed. But the president not leaving before weighing in, of course, on that other history-making moment. His former lawyer and fixer, Michael Cohen's testimony on capitol hill. The president blasting Cohen but sharing kind words about Kim Jong-un. And this even though they could not reach an agreement. Our chief white house correspondent Jonathan Karl is there in Hanoi with the latest. Good morning, Jon. Reporter: Good morning, robin. The headline here, no deal. The president continues to call Kim Jong-un a friend. But he told reporters just a short while ago sometimes you have to walk. There were handshakes and smiles but the summit came to an abrupt end without any agreement. Not even a joint statement. I think actually it was a productive two days but sometimes you have to walk and this was just one of those times. Reporter: There was a fundamental disagreement. Kim Jong-un wants the crushing sanctions on his country lifted before dismantling his nuclear program. Basically they wanted the sanctions lifted in their entirety, and we couldn't do that. They were willing to denuke a large portion of the areas that we wanted but we couldn't give up all of the sanctions for that. Reporter: No agreement but the president continued to talk warmly of the north Korean dictateer. We spent pretty much all day with Kim Jong-un, who is -- he's quite a guy and quite a character and I think our relationship is very strong. Reporter: If Kim is quite a guy, he is also the absolute ruler of perhaps the most repressive regime on the planet. One blamed for the death of American college student Otto Warmbier, who spent more than two years in a north Korean prison and died shortly after he was released with brain damage and in a coma in 2017. I don't believe that he would have allowed that to happen. He felt very badly. He knew the case very well but he knew it later. Got a lot of people. Big country. A lot of people. And in those prisons and those camps you have a lot people and some really bad things happened to Otto. Some really, really bad things but he tells me, he tells me he didn't know about it and I will take him at his word. Reporter: Earlier Kim for the first time took questions from the western press responding through a translator. Chairman Kim, are you ready to denuclearize? Translator: If I'm not willing to do that I won't be here right now. Good answer. That might be the best answer you've ever heard. Reporter: The questions kept coming. A member of the north Korean delegation motioned for the press to leave and Kim seemed uncomfortable to be put on the Chairman Kim, are you ready to allow the United States to have an office in Pyongyang? Are you ready for that step? Translator: Is it better to leave -- let the -- That's an interesting question. I would like to actually hear that answer because it's not a bad idea. Translator: Well, I think that is something which is welcomeable. Reporter: He still hopes to strike a deal with Kim Jong-un that rids North Korea of its nuclear weapons. But there is not even a date for another summit meeting, in fact, the president was asked if he had committed to meeting again with Kim Jong-un, and he said, no, no such commitment. At least not now. Robin. All right, Jon, thanks very much. Stand by. I want to bring in Martha Raddatz as well also in Hanoi with you and, Martha, of course, a lot of disappointment there was no deal struck on the nuclear weapons but there has to be some relief among the president's team he didn't make too many concessions to get a win. Reporter: Exactly, George. There were concerns that president trump wanted to deal so badly he may have backed off some of the demands that clearly did not happen but the same time this abrupt ending today showed just how far apart the U.S. And North Korea are in their understanding of what happened at the first summit in June. The administration then saying Kim was willing to denuclearize before sanctions relief. Now we know that Kim saw the deal differently or has now changed the conditions for the deal. The president said the nuclear threat from North Korea was over. Jon, it seems like this personal relationship with the president -- between the president and Kim is kind of evolving, still warm in some ways but pushing in others. Reporter: Yeah, extraordinary moment we saw, first of all, Kim Jong-un as far as we know has never taken a question from the western press, at least not before today. He was asked a question about opening a -- several questions but one was about opening a U.S. Office in North Korea. He clearly didn't want to answer it. The north Korean minders were starting to push the press out and the president said, wait, I'd like to hear the answer to this. Really an interesting moment. Perhaps some unfamiliarity, the president liking to put Kim Jong-un on the spot. Martha, the terror of the Kim regime so well known but the president still not willing to push there. Reporter: He really isn't and a year ago, of course, he was talking a lot about how terrible Kim Jong-un is and the regime there. Now he just avoids those questions, although that answer to the Otto Warmbier question was just truly remarkable, George. Martha Raddatz, Jon Karl, thanks very much. Called the prison camp rough places. One historic moment playing out while another was under way

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