US President Donald Trump shook hands with North Korean leader Kim Jong Un at the start of their second summit Wednesday, saying the totalitarian state could enjoy a brilliant future if it gives up nuclear weapons.
Trump predicted a "very successful" summit as the pair prepared for dinner at the luxury Sofitel Legend Metropole hotel in Hanoi to follow up on their initial historic meeting in Singapore in June.
In a brief sit-down ahead of one-on-one talks, Trump repeated his view that North Korea had "tremendous" economic potential.
For his part, Kim pledged to do his "best" to achieve an outcome that "will be welcomed by all people."
They were due to open with about 20 minutes of head-to-head talks before sitting around a table with only a handful of top advisers. Negotiations were then scheduled to resume on Thursday.
Earlier, Trump sent a tweet touting North Korea's "AWESOME" potential if his "friend" Kim agrees to relinquish his weapons.
The president risks being distracted by scandal back in Washington, where his former lawyer Michael Cohen was set to describe him as a "conman" in bombshell testimony to Congress scheduled for shortly after the summit dinner ends on the other side of the world.
But Trump, seeking a big foreign policy win to push back against domestic troubles, believes he can make history with North Korea -- and claims Japan's prime minister has already nominated him for a Nobel Peace Prize.
His goal is to persuade Kim to dismantle his nuclear weapons and resolve a stand-off with the totalitarian state that has bedevilled US leaders since the end of the Korean war in 1953.
To lure Kim into radical change, Trump is believed to be considering offering a formal peace declaration -- though perhaps not a formal treaty -- to draw a line under the technically still unfinished war.
At the same time, Washington faces mounting pressure to extract significant concessions from Kim, who has so far shown little desire to ditch his nuclear capability.
China's Foreign Minister Wang Yi said Wednesday the Hanoi meeting could be "an important step towards advancing the denuclearisation" of the Korean peninsula.
However, Washington and Pyongyang disagree even on what denuclearisation means precisely. And while North Korea has now gone more than a year without conducting missile and nuclear tests, it has done nothing to roll back the weapons already built.
A former real estate tycoon who often boasts he is one of the world's best negotiators, Trump is pitching a vision of North Korea as a new Asian economic tiger if it surrenders its nuclear status.
He said the country could quickly emulate the summit's host, Vietnam -- a communist state once locked in devastating conflict with the United States, but now a thriving trade partner.
And he has invested himself personally in the relationship with Kim, creating the diplomatic equivalent of a Hollywood odd-couple bromance.
Before Singapore, they were slinging bizarre insults -- Trump calling Kim "rocket man" and Kim calling him a "dotard." With North Korea then busily testing missiles and conducting underground nuclear tests, analysts feared the duo were egging each other on towards a catastrophic confrontation.
Now, Trump talks of "love" and claims that his ground-breaking policies defused the threat posed by Kim.
Critics warn Trump is so keen to score a deal that he could give away too much, too quickly, endangering US allies South Korea and Japan.
In Singapore, Trump took his own generals by surprise when he announced a suspension of military exercises with the South -- something the North badly wanted.
Washington would ideally like Kim to dismantle a key nuclear facility at Yongbyon, allow in international inspectors, or even hand over a list of all his nuclear assets -- something the North Koreans have categorically refused to do.
In return, Trump is believed to be considering dangling relief from tough international sanctions. Opening diplomatic liaison offices is another possible US concession.
Another possibility is a joint declaration to end the Korean War, which closed with a ceasefire but no peace treaty Some analysts fear this hugely symbolic gesture would upset the delicate power balance in a region where the US and China are already struggling for influence.
Those pushing for a scaled-back US foreign policy footprint around the world would welcome the gambit.
"If you get an end of war declaration, I think that's really important symbolically because it starts to change the mentality," Daniel Davis, at the conservative Washington-based Defense Priorities think tank, told AFP.
And Trump deserves credit, he said.
"You just can't ignore the fact that he's the only one of the last nine American presidents that has even gotten to this point. No one else has even had the conversations, no one else has had these summits."