US President Donald Trump says he walked away from a deal at a summit with North Korean leader Kim Jong-un because of unacceptable DPRK demands to fully lift US-led sanctions.

President Donald Trump meets North Korean leader Kim Jong-un, February 28, 2019, in Hanoi.
President Donald Trump meets North Korean leader Kim Jong-un, February 28, 2019, in Hanoi. (AP)

The nuclear summit between US President Donald Trump and the Democratic Republic of Korea's Kim Jong-n ended abruptly on Thursday after the two sides failed to reach a deal due to a standoff over US sanctions on North Korea, an unexpected end to high-stakes meetings meant to disarm a global threat.

Trump, in a news conference after the talks ended early, said the breakdown occurred over the DPRK's insistence that all punishing sanctions the US had imposed on North Korea be lifted without Pyongyang committing to eliminate its entire nuclear arsenal.

"Sometimes you have to walk," Trump explained, adding that an agreement was "ready to sign."

"I'd much rather do it right than do it fast," the president said. "We're in position to do something very special."

Both leaders motorcades roared away from the downtown Hanoi summit site within minutes of each other after both a lunch and the signing ceremony were scuttled. Trump's closing news conference was moved up. He was expected to depart for Washington ahead of schedule.

The breakdown came after Trump and Kim had appeared to inch toward normalising relations between their still technically-warring nations as the American leader tamped down expectations that their talks would yield an agreement by North Korea to take concrete steps toward ending its nuclear program.

In something of a role reversal, Trump deliberately ratcheted down some of the pressure on Pyongyang, abandoning his fiery rhetoric and declaring he wanted the "right deal" over a rushed agreement.

For his part, Kim, when asked whether he was ready to denuclearise, said "If I'm not willing to do that I won't be here right now."

The failure to make a deal denied Trump a much-needed victory that could have offset some of the growing domestic turmoil back home.

But he insisted that relations with Kim remained warm, stressed that progress had been made and said he was still hopeful of eventually reaching a deal to denuclearise North Korea.

TRT World 's Patrick Fok reports from Vietnam.

Was Trump distracted by Cohen?

The unexpected end to the summit with Kim raised questions whether the US president might have been distracted by his ex-fixer and ex-lawyer Michael Cohen who was testifying to Congress against his former boss while Trump was meeting the North Korean leader.

"He [Cohen] lied a lot," Trump told a press conference in Vietnam after the summit concluded

TRT World's Jon Brain has more from Washington DC.

Markets lower

News of the summit failure sent South Korea's currency lower and knocked regional stock markets. South Korea's Kospi index closed 1.8 percent lower, marking the biggest one-day percentage loss since October 2018.

While Trump indicated a more flexible stance in the run-up to the Hanoi summit, critics had warned that he risked squandering vital leverage over North Korea if he gave away too much, too quickly.

US intelligence officials have said there is no sign North Korea would even give up its entire arsenal of nuclear weapons, which analysts believe is vital to the survival of the Kim family, history's only communist dynasty to date.

While Washington has long demanded that the DPRK give up all of its nuclear and missile programmes, Pyongyang wants to see the removal of a US nuclear umbrella for its Asian allies such as South Korea and Japan.

Source: TRTWorld and agencies