Donald Trump has revealed that Hanoi will be the venue for his second summit with Kim Jong-un later this month.
The US president had said in the State of the Union address on Tuesday that he would meet the North Korean leader in Vietnam from February 27-28.
There had been speculation that Da Nang would be the location for the high-profile meeting.
In a tweet that disclosed the northern Vietnam city of Hanoi as the venue, Mr Trump said he was looking "forward to seeing Chairman Kim & advancing the cause of peace!"
He added: "North Korea, under the leadership of Kim Jong Un, will become a great Economic Powerhouse. He may surprise some but he won’t surprise me, because I have gotten to know him & fully understand how capable he is. North Korea will become a different kind of Rocket - an Economic one!"
The US special representative for North Korea had just wrapped up three days of talks in Pyongyang to prepare the second summit.
The State Department said Stephen Biegun had agreed with his counterpart Kim Hyok Chol to meet again ahead of the meeting.
In their talks in Pyongyang from Wednesday until Friday Mr Biegun and Kim Hyok Chol "discussed advancing President Trump and Chairman Kim's Singapore summit commitments of complete denuclearisation, transforming US-DPRK relations, and building a lasting peace on the Korean Peninsula." the State Department said.
Its statement, which referred to North Korea by the acronym for its official name, the Democratic People's Republic of Korea, gave no indication of any progress in the talks.
Just weeks ahead of the planned summit to follow on from an unprecedented first meeting between the leaders in Singapore last June, the two sides have appeared far from narrowing differences over US demands for North Korea to give up a nuclear weapons program that threatens the United States.
Mr Biegun said last week his Pyongyang talks would be aimed at seeking progress on commitments made in Singapore and mapping out "a set of concrete deliverables" for the second summit.
He said Washington was willing to discuss "many actions" to improve ties and entice Pyongyang to give up its nuclear weapons and that Mr Trump was ready to end the 1950-53 Korean War, which concluded with an armistice, not a peace treaty.
Mr Biegun said Kim committed during an October visit by US Secretary of State Mike Pompeo to the dismantling and destruction of plutonium and uranium enrichment facilities and that "corresponding measures" demanded by North Korea would be the subject of his talks.
At the same time, he set out an extensive list of demands that North Korea would have to meet eventually, including full disclosure of its nuclear and missile programmes, something Pyongyang has rejected for decades.
Mr Trump, eager for a foreign policy win to distract from domestic troubles, has been keen for a second summit despite a lack of significant moves by North Korea to give up its nuclear weapons programme. He and Mr Biegun have stressed the economic benefits to North Korea if it does so.
The Singapore summit yielded a vague commitment by Kim to work toward the denuclearization of the Korean peninsula, where US troops have been stationed since the Korean War.
While in the US view North Korea has yet to take concrete steps to give up its nuclear weapons, Pyongyang complains that Washington has done little to reciprocate for its freezing of nuclear and missile testing and dismantling of some facilities.
Pyongyang has repeatedly urged a lifting of punishing US-led sanctions, a formal end to the war, and security guarantees.
South Korea's Yonhap News agency quoted that country's foreign ministry as saying that Mr Biegun arrived back in Seoul from Pyongyang on Friday evening, Seoul time, and would meet with South Korean Foreign Minister Kang Kyung-wha on Saturday morning to provide a briefing on the results of his talks.