– Secretary of State Mike Pompeo said Wednesday that the Trump administration hopes to complete "major disarmament" of North Korea within the next 2½ years, even as conflicting accounts of discussions between the two sides left unclear what had actually been agreed to.

A day after President Donald Trump's landmark meeting with North Korea's leader, Kim Jong Un, in Singapore, the two leaders and their governments sought to shape the understanding of their talks to their advantage. But the contours of the vague agreement remained unclear and open to divergent interpretations.

North Korea's state-controlled news media said Trump had agreed to a phased, "step by step" denuclearization process rather than the immediate dismantling of its nuclear capability, with the United States providing reciprocal benefits at each stage along the way. Trump has previously insisted he will not lift sanctions until North Korea has rid itself of its nuclear weapons.

The Trump administration, for its part, insisted the general wording of the joint statement signed by Trump and Kim committed North Korea to an intrusive inspection regime to confirm its "complete denuclearization." The statement itself, however, did not explicitly use the words "verifiable" or "irreversible" that had been part of the mantra of U.S. officials leading up to the Singapore summit.

"Let me assure you that the 'complete' encompasses 'verifiable' in the minds of everyone concerned," Pompeo told reporters in Seoul, where he flew to consult with South Korean officials. "One can't completely denuclearize without validating, authenticating — you pick the word."

The president himself did not dwell on the details as he landed back in Washington early Wednesday morning. Instead, he claimed a sweeping achievement even before any of the details have been worked out.

"Just landed — a long trip, but everybody can now feel much safer than the day I took office," he wrote on Twitter. "There is no longer a Nuclear Threat from North Korea."

His claim that there was no longer a nuclear threat came even though North Korea has not given up any of its weapons or dismantled any of its 141 known nuclear facilities other than blowing up a test site. Trump's assertion drew derision from critics who accused him of getting way ahead of what could be a long, difficult negotiation to translate the gauzy aspiration of Singapore into a workable plan.

"What planet is the president on?" asked Sen. Chuck Schumer, D-N.Y., the minority leader. "Saying it doesn't make it so. North Korea still has nuclear weapons. It still has ICBMs. It still has the United States in danger. Somehow President Trump thinks when he says something it becomes reality. If it were only that easy, only that simple."

Lawmakers and allies alike were left trying to discern what exactly Trump agreed to and how the follow-up negotiations would proceed. Pompeo planned to brief South Korean officials who were caught off guard to learn the president had agreed to suspend joint military exercises in a significant concession to North Korea.

"The critical question is what comes next?" said Kelsey Davenport, nonproliferation policy director at the Washington-based Arms Control Association. "The true test of success is whether the follow-on negotiations can close the gap between the United States and North Korea on the definition of denuclearization and lay out specific, verifiable steps that Pyongyang will take to reduce the threat posed by its nuclear weapons."

The agreement signed Tuesday lacks any detail on the central issue, denuclearization, raising fears among analysts that once negotiators wade into the specifics, the talks could end in stalemate, as they have after past nuclear disarmament accords. South Korean officials hope that the two strong-willed leaders will push the process ahead, with an eye on their legacies.

Kim needs to improve ties with Washington and lift sanctions if he wants to keep his promise to develop North Korea's economy. Trump, meanwhile, has repeatedly boasted that he would resolve a problem his predecessors could not.

Trump has recently acknowledged that denuclearization could take time. In an interview with ABC News, Trump also said North Korea planned to "get rid of certain ballistic missile sites and various other things." As of Wednesday, there had been no announcement from North Korea about removing such facilities.