President Trump’s second denuclearization summit with North Korean leader Kim Jong-un fell apart Thursday in a dispute over lifting economic sanctions, cutting short two days of talks aimed at dismantling Pyongyang’s weapons program.

After several hours of discussions, Mr. Trump and Mr. Kim abruptly parted ways over North Korea’s demand that the U.S. lift crushing sanctions in exchange for something less than the full dismantling of all Pyongyang’s weapons sites.

“Basically, they wanted the sanctions lifted in their entirety, and we couldn’t do that,” Mr. Trump said at a press conference in Hanoi. “They were willing to denuke a large portion of the areas that we want, but we couldn’t give up all of the sanctions for that.”

Mr. Trump added, “Sometimes you have to walk. And this was just one of those times. I’d much rather do it right than do it fast.”

The collapse of the talks without any agreement was a disappointment, after months of high-level negotiations since the two leaders’ breakthrough summit last June in Singapore. Mr. Kim pledged at that first meeting to denuclearize, but since then he has resisted accepting the U.S. definition of complete and verifiable eradication of his weapons.

The international sanctions limit North Korea’s ability to import oil, and to sell its chief export, coal. Mr. Trump has held the sanctions tightly as his primary leverage in negotiations.