HANOI, Vietnam: In open dispute, the US and North Korea offered contradictory accounts Thursday of why the summit between Donald Trump and Kim Jong Un broke down, though both pointed to punishing American sanctions as a sticking point in the high-stakes nuclear negotiation. President Trump, who returned to the White House Thursday night, said before leaving Hanoi that the talks collapsed because North Korea’s leader insisted that all the sanctions the US has imposed on Pyongyang be lifted without the North firmly committing to eliminate its nuclear arsenal. But North Korea challenged that account, insisting it had asked only partial sanctions relief in exchange for shutting down its main nuclear complex. Foreign Minister Ri Yong Ho commented on the talks during an abruptly scheduled middle-of-the-night news conference after Trump was in the air. Ri said the North was also ready to offer in writing a permanent halt of the country’s nuclear and intercontinental ballistic missile tests and Washington had wasted an opportunity that “may not come again.” He said the North’s position won’t change even if the United States offers to resume another round of dialogue. On Friday, North Korea’s official news agency put a more positive spin on the summit, saying Trump and Kim “had a constructive and candid exchange of their opinions over the practical issues arising in opening up a new era of the improvement” of relations between the two nations. Trump made no mention of the disagreement as he addressed US troops during a stopover at Joint Base Elmendorf-Richardson in Alaska, though White House spokeswoman Sarah Sanders said he was aware of Ri’s comments. Instead, Trump focused on US military might and offered a broad warning to US enemies. “America does not seek conflict, but if we are forced to defend ourselves we will fight and we will win in an overwhelming fashion,” he declared. Earlier on Thursday in Hanoi, Trump had told reporters the North had demanded a full removal of sanctions in exchange for shutting the Yongbyon nuclear facility. Trump said that there had been a proposed agreement “ready to be signed.” However, he said after the summit was cut short, “Sometimes you have to walk.” The demise of the talks came after Trump and Kim had appeared ready to inch toward normalizing relations between their still technically warring nations. The American leader had dampened expectations that the negotiations would yield an agreement by North Korea to take concrete steps toward ending a nuclear program that Pyongyang likely sees as its strongest security guarantee. However, Kim, when asked whether he was ready to denuclearize, had said, “If I’m not willing to do that I won’t be here right now.” But hours after both nations had seemed hopeful of a deal of some kind, the two leaders’ motorcades roared away from the downtown Hanoi summit site within minutes of each other, lunch canceled and signing ceremony scuttled. The president’s closing news conference was hurriedly moved up, and he departed for Washington more than two hours ahead of schedule. The breakdown denied Trump a much-needed triumph amid growing political turmoil back home and the path forward now appears uncertain. Trump insisted his relations with Kim remain warm, but he did not commit to having a third summit with the North Korean leader, saying a possible next meeting “may not be for a long time.” Ri’s comments reflected the North Koreans’ disappointment, though there was a notable absence of bluster or threats by either side. Both Trump and Secretary of State Mike Pompeo said significant progress had been made in Hanoi, but the two sides appeared to be galaxies apart on an agreement that would live up to stated American goals. “Basically, they wanted the sanctions lifted in their entirety, and we couldn’t do that,” Trump told reporters. Kim, he said, appeared willing to close his country’s main nuclear facility, the Yongbyon Nuclear Scientific Research Center, if the sanctions were lifted. But that would leave him with missiles, warheads and weapon systems, Pompeo said. There are also suspected hidden nuclear fuel production sites around the country. “We couldn’t quite get there today,” Pompeo said, minimizing what seemed to be a chasm between the two sides. Longstanding US policy has insisted that US sanctions on North Korea would not be lifted until that country committed to, if not concluded, complete, verifiable and irreversible denuclearization. Trump declined to restate that goal Thursday, insisting he wanted flexibility in talks with Kim. Ri said North Korea proposed that US and North Korean technicians jointly dismantle plutonium, uranium-enrichment and other nuclear material-making facilities at Yongbyon in the presence of US experts. He said it is “the biggest denuclearization measure that we can take” given the current status of mutual confidence between the two countries. In return, Ri said North Korea asked the US to lift five kinds of sanctions that are related to its civilian economy and public livelihoods. The failure in Hanoi laid bare a risk in Trump’s negotiating style. Preferring one-on-one meetings with his foreign counterparts, his administration often eschews the staff-level work usually done in advance to assure a deal. There was disappointment and alarm in South Korea, whose liberal leader has been a leading orchestrator of the nuclear diplomacy and who needs a breakthrough to restart lucrative engagement projects with the impoverished North. Yonhap news agency said that the clock on the Korean Peninsula’s security situation has “turned back to zero” and diplomacy is now “at a crossroads.” The two leaders had seemed to find a point of agreement when Kim, who fielded questions from American journalists for the first time, was asked if the US may open a liaison office in North Korea. Trump declared it “not a bad idea,” and Kim called it “welcomable.” Such an office would mark the first official US presence in North Korea and a significant grant to a country that has long been deliberately starved of international recognition. There had long been skepticism that Kim would be willing to give away the weapons his nation had spent decades developing and Pyongyang felt ensured its survival. But even after the summit ended, Trump praised Kim’s commitment to continue a moratorium on missile testing. ___ Follow Lemire on Twitter at http://twitter.com/@JonLemire , Riechmann at http://twitter.com/@debriechmann and Klug at http://twitter.com/@APklug ___ Follow all of AP’s summit coverage: https://apnews.com/Trump-KimSummit