WASHINGTON – North Korea’s foreign minister on Thursday contradicted President Donald Trump's account of the failed negotiations in Hanoi.

During a rare statement to the international media in Vietnam, Foreign Minister Ri Yong Ho said the North Koreans offered more – and asked for far less – than the way Trump characterized the proposal. He also suggested it would be difficult to restart the negotiations.

“It became crystal clear that the United States was not ready to accept our proposal,” Ri said through a translator. “Our proposal will never be changed, even though the United States proposes negotiation again in the future.”

Start your day smarter:Get USA TODAY's Daily Briefing in your inbox

Trump had said North Korean leader Kim Jong Un asked for a full lifting of economic sanctions on his government. In exchange, Trump said, Kim offered to dismantle North Korea's main nuclear facility, Yongbyan. But Kim would not commit to giving up North Korea's stockpile of nuclear bombs, its missiles or its other capabilities, the president said.

Ri told reporters that North Korea had offered to permanently dismantle all its nuclear material production, including plutonium and uranium, around the Yongbyan facility under observation by U.S. experts. And Kim only asked for partial relief from the multilateral sanctions, he said.

In response to Ri’s comments, a senior State Department official said the North Koreans were “parsing words.” This official, who spoke on the condition of anonymity to discuss private negotiations, said the North Koreans asked for the lifting of all sanctions except those on weapons.

Editorial:At North Korea summit, flattery got Trump nowhere

Opinion:President’s diplomatic approach to North Korea is artful

Fact check:Trump says North Korea summit 'productive.' Was it?

That would have included “a broad range of products including metals, raw materials, transportation, seafood, coal exports, refined petroleum imports, raw petroleum imports … It tallies up to the tune of many, many billions of dollars,” the official said.

That would have put the U.S. in the position of subsidizing North Korea’s ongoing development of weapons of mass destruction.

The differences over such details did not spell an end to the talks, the State Department official said. He argued North Korea’s account of the summit, as reported in the country’s state owned media, seemed constructive. “There’s still ample opportunity to talk,” he said.

Scott A. Snyder, a Korea expert at the Council on Foreign Relations, a foreign policy think tank, said it's hard to know whether Ri's comments were revisionist or reality.

The North Koreans may have realized "it was overreach" to ask for full sanctions relief and Ri's comments were an attempt to scale that request back, Synder said. But it could also be "a more factual description of what the North Koreans were after" than what Trump gave.

Otto Warmbier:Trump believes Kim Jong Un didn't know about Otto Warmbier. Experts say that's impossible.

'I don't believe he knew about it.':Trump defends Kim Jong Un on Otto Warmbier's death

The North Korean official's comments came after a high-stakes summit in Hanoi ended abruptly with no agreement. The White House cancelled a signing ceremony, planned for Thursday with Trump and Kim. At his own a news conference, Trump conceded the two leaders could not reach an agreement that would lead to the denuclearization of the Korean Peninsula.

"Sometimes you have to walk," Trump told reporters. He said Kim's offer to dismantle Yongbyon did not go far enough.

“That facility, while very big, it wasn’t enough to do what we were doing,” Trump told reporters Thursday.

Ri did not take any questions from reporters, ignoring a shouted query about how North Korean officials could be unaware of Otto Warmbier's detention and condition after he was imprisoned there. Warmbier was arrested in North Korea in 2016 after visiting the country with a tourist group. He suffered a severe brain injury and died days after the North Koreans released him in 2017.

Trump said he raised Warmbier's case with Kim but the North Korean dictator denied knowing anything about it. "He tells me that he didn't know about it, and I will take him at his word," Trump said.

Trump's acceptance of Kim's answer has sparked backlash from lawmakers in both parties.

More:North Korea summit: Why Trump's failure to reach a deal is being lauded in Washington

More:'Unacceptable.' Backlash builds against Trump remarks on mistreatment of Otto Warmbier in North Korea