HANOI — Two days of soaring rhetoric and over-the-top flattery between President Trump and North Korean leader Kim Jong Un turned to finger-pointing Thursday after their second summit ended in stalemate and confusion, an outcome the president’s critics say he should have seen coming.

Trump said North Korea’s demand for total relief from sanctions in exchange for partially dismantling its nuclear weapons program was the main stumbling block to an agreement. 

“Basically they wanted the sanctions lifted in their entirety, and we couldn’t do that,” Trump said at a news conference before leaving Vietnam. “You always have to be prepared to walk.”

Trump said Kim promised he would not conduct missile launches or test nuclear weapons, and U.S. officials said the two sides would continue to talk. But North Korean Foreign Minister Ri Yong Ho was noncommittal.

Holding a separate news conference with international reporters — a remarkable step for the secretive authoritarian state — Ri blamed the United States for the breakdown. He also disputed Trump’s characterization of North Korea’s request.

“What we proposed was not the removal of all sanctions, but a partial removal,” Ri said through an interpreter. 

In exchange, Ri said, North Korea would “permanently and completely dismantle all the nuclear material production facilities” at the Yongbyon nuclear facility. The compound houses the country’s main nuclear reactor, which is the regime’s only source of plutonium, as well as some —but not all —of its uranium-enrichment facilities. It does not include warheads or missile inventory. 

A senior administration official, who briefed reporters after Ri’s news conference, disputed his account, saying that North Korea wanted virtually all U.N. sanctions lifted, in exchange for what was only a  partial closure of the many-faceted Yongbyon compound.

The sanctions request, first made during the past week in working-level talks, included “metals, raw materials, transportation, seafood, coal exports, refined petroleum imports, raw petroleum imports . . . it was basically all the sanctions except armaments,” said the official, who asked to be anonymous under State Department guidelines for the briefing.

“The dilemma we were confronted with,” the official said, was effectively to subsidize “the ongoing development of weapons of mass destruction in North Korea.”

Trump “encouraged Chairman Kim to go all in. And we were prepared to go all in as well,” the official said.

Secretary of State Mike Pompeo said that the United States hadn’t softened its demand for a full accounting of North Korea’s nuclear program and that Trump had walked into the session clear-eyed about how far Kim was likely to go.

The two-day summit ended a few hours early and without a planned joint statement memorializing progress. 

“We worked through the night,” Pompeo said. “We were very hopeful we’d make enough progress that it would justify a signing statement at the ultimate concluding, and we didn’t. The president made that decision.”

It was not until a half-hour before the two leaders were to have a celebratory lunch — with the table already set — that the White House announced “a program change.”

The chicken-and-egg problem of when the strapped North Korean regime is rewarded, and for what, is the central element of a deal that has eluded previous U.S. presidents. North Korea wants more upfront than U.S. negotiators are willing to give, and it fell to Trump and Kim to try to meet in the middle.

That was never going to work without more preparation and bottom-up planning, said Scott Snyder, a Korea expert at the Council on Foreign Relations. 

“I think the failure was an admission of a need for more time and working-level talks to achieve an agreement,” Snyder said. “It lets the North Koreans know that summitry has to be accompanied by process and that an end run around working-level talks and exclusive focus on the leader level won’t necessarily yield results.”

Pompeo insisted that the United States has put in that grunt work and was not sandbagged.

Asked why the two sides did not come to an interim agreement, Pompeo said, without elaboration, that “you should not assume that we didn’t come to agreement on a whole number of issues.”

Pompeo said that no date had been set for ongoing talks. 

“My sense is, it’ll take a while,” he said. “We’ll each need to regroup a little bit.”

The abrupt end to the summit may have exposed the limits of Trump’s strategy to appeal directly to Kim, whom he used to ridicule as “Little Rocket Man” but now praises as a savvy leader who could preside over his country’s economic transformation. Trump said the two parted on friendly terms, but he did not dangle a White House invitation or other perks as he did following their first meeting last year.

“Good personal rapport is good, but it’s not enough to bridge big gaps in the course of one high-level summit,” said Daryl Kimball, executive director of the Washington-based Arms Control Association.

Trump could claim success after the leaders’ first summit in Singapore simply because the historic meeting had happened at all, said Bruce Jentleson, a professor of public policy and political science at Duke University and a former State Department adviser.

This time, they needed more than the symbolism of grins and handshakes replacing threats of “fire and fury,” Jentleson said.

“You don’t set up a summit this way and be surprised like that,” Jentleson said. “You do the prep work, you have a degree of agreement beforehand.” 

To some extent, Trump backed himself into a corner last year by saying that any deal with North Korea must be all or nothing — complete denuclearization in exchange for any lifting of sanctions.

“It was a good tactical position to start with . . . but an untenable position to maintain throughout negotiations,” said a former U.S. intelligence official, speaking on the condition of anonymity to avoid becoming involved in the politics of the issue. “The question was always going to be, when do we soften, and how do we do it in a way so that we can say with a straight face that we’re not lifting sanctions, but make enough modifications so that we can actually get something back” from the North Koreans.

Kim came with a step-by-step proposal that included the verified shutdown of Yongbyon — which the former official said was “a big thing, it’s not a little thing” — and asked for partial sanctions relief in return. But such agreements “require negotiations,” and the summit apparently ran out of time.

“It’s a disappointment, and maybe a step backwards, but it doesn’t feel like they’re breaking off the entire process,” the former official said. “The fact that they couldn’t meet unrealistic expectations shouldn’t divert us from understanding that apparently they may try this at the working level.”

Sue Mi Terry and Lisa Collins, fellows on Korea at the Center for Strategic and International Studies, assessed the summit as a failure that could “make it very difficult to move negotiations forward at the working level since the discussions on even basic principles have failed at the highest leadership level.”

Until it is clear how North Korea’s state media will play the summit, they wrote in a CSIS briefing paper Thursday, there is no clear way forward from an apparent stalemate. 

“North Korea is the land of lousy options,” they said. “So far President Trump has been no more successful than his predecessors.”

In the absence of progress, experts worry that tensions could rise again.

“How are Stephen Biegun and Kim Hyok Chol going to close a gap that Donald Trump and Kim Jong Un couldn’t?” said John Delury, a Korea expert at Yonsei University in Seoul, referring to the U.S. special representative for North Korea appointed by Trump to negotiate an agreement and his North Korean counterpart.

In the past several months, ­lower-level talks have been slow to make progress, as junior North Korean diplomats have lacked the negotiating authority to make concessions, said diplomats familiar with the talks.

The North Korea issue has divided Trump’s top advisers and America’s closest allies, who have tried to push the president in different directions.

National security adviser John Bolton is a staunch opponent of the talks and skeptical of Biegun.

Bolton and like-minded officials at the Treasury Department and Pentagon had expressed concern that Biegun was moving too fast in looking to loosen sanctions or agreeing to an end-of-war declaration, according to people familiar with the discussions. Defenders of Biegun said he is a pragmatist and seasoned negotiator who privately acknowledges the steep odds of a successful outcome.

South Korean President Moon Jae-in has invested a huge amount of his personal prestige in engagement with North Korea. He is certain to be enormously disappointed in the breakdown of the talks.

Trump spoke by phone to both Moon and Japanese Prime Minister Shinzo Abe, whose government had expressed skepticism about the talks, as he flew home Thursday.

Moon spokesman Kim Eui-keum called it “regrettable” that Trump and Kim Jong Un were not able to reach “complete agreement” at the talks and said he hoped the two sides would continue to talk. But a South Korean presidential adviser offered a franker assessment.

“I was flustered,” said Kim Kwang-gil, a sanctions expert on the Presidential Committee on Northern Economic Cooperation. “So many people in South Korea who took hopes in this summit . . . are left heartbroken.”

Gearan reported from Washington. Karen DeYoung in Washington and Philip Rucker and David Nakamura in Hanoi contributed to this report.