Donald Trump has said a deal with North Korea could be a "very good one for the world" a day after agreeing to meet with Kim Jong Un in the coming weeks.
He tweeted on Saturday: "The deal with North Korea is very much in the making and will be, if completed, a very good one for the World. Time and place to be determined."
It comes after South Korea's national security adviser Chung Eui Yong announced at the White House Mr Kim's desire to meet with Mr Trump and his "commitment to denuclearisation" following talks in Pyongyang on Monday.
The deal with North Korea is very much in the making and will be, if completed, a very good one for the World. Time and place to be determined.
— Donald J. Trump (@realDonaldTrump) March 10, 2018
The US President's latest comments come after the White House looked to dismiss criticism that the US was getting nothing in return for agreeing to a summit with the North Korean leader.
But Press Secretary Sarah Sanders reminded reporters North Korea had committed to denuclearisation, promised to stop missile testing and allow US-South Korea military exercises to continue.
She said: "Let's not forget that the North Koreans did promise something… we are not going to have this meeting take place until we see concrete actions that match the words and the rhetoric of North Korea."
On Friday, the White House also confirmed Mr Trump discussed the North Korea issue with Chinese President Xi Jinping and "welcomed the prospect" of a dialogue, despite no serving US President having ever met with a North Korean leader before.
They also committed to keeping pressure and sanctions in place until North Korea takes "tangible steps" towards "complete, verifiable and irreversible denuclearisation".
White House legislative affairs director Marc Short said President Trump's decision to meet with Mr Kim was made with a "handful" of lawmakers. He said while the White House hoped the encounter would "bear fruit", officials would remain "cautious".
The historic meeting – expected to take place by May – follows the two leaders trading insults for months and economic sanctions on North Korea being ramped up in response to its nuclear weapons programme.
Mr Trump had previously threatened "fire and fury" in response to threats from North Korea. Mr Trump also referred to the North Korean leader as "Little Rocket Man".
But on Friday, the US leader tweeted: "Kim Jong Un talked about denuclearisation with the South Korean representatives, not just a freeze.
"Also, no missile testing by North Korea during this period of time. Great progress being made but sanctions will remain until an agreement is reached. Meeting being planned!"
US Vice President Mike Pence said the move was "evidence that President Trump's strategy to isolate the Kim regime is working".
"Our resolve is undeterred and our policy remains the same: all sanctions remain in place and the maximum pressure campaign will continue until North Korea takes concrete, permanent, and verifiable steps to end their nuclear programme," he said.
The European Union, Russia and South Korea have welcomed the shift in US-North Korea relations.
South Korea's Foreign Minister Kang Kyung Wha said her government was working with the US in order to ensure a "meaningful meeting with a good outcome".
South Korean President Moon Jae In said a meeting between Mr Trump and Mr Kim would be a "historical milestone" that will put the denuclearisation of the Korean Peninsula "really on track".
However, some politicians and experts have voiced scepticism over the meeting.
Bruce Klingner, a Korea expert at the Heritage Foundation think tank, said: "A presidential visit is really the highest coin in the realm in diplomacy circles… Trump seemed to spend it without getting anything in return, not even the release of the three US captives."
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Former senior State Department official Evans Revere, who has experience of negotiating with North Korea, warned there could be a disconnect between how the two parties describe denuclearisation.
He said for the US it meant North Korea giving up their weapons, and for North Korea it meant also removing the threat of US forces in South Korea and its nuclear deterrent in the region.