Vice Chairman Kim Yong Chol, a right-hand man to the North Korean leader, met with Trump at the White House for an unusually long 90 minutes as the countries seek a denuclearization accord that could ease decades of hostility.

"The president looks forward to meeting with Chairman Kim at a place to be announced at a later date," Trump spokeswoman Sarah Sanders said in a statement, revealing that the summit would take place "near the end of February."

The latest flurry of diplomacy comes little more than a year after Trump was threatening to wipe North Korea off the map, with Pyongyang's nuclear and missile tests rattling nerves in East Asia.

Kim Jong Un and Trump held a landmark first meeting in June in Singapore, where they signed a vaguely worded document, with Kim pledging to work towards the "denuclearization of the Korean peninsula."

But progress stalled soon afterward as Pyongyang and Washington -- which stations 28,500 troops in South Korea -- disagree over what that means.

Kim Yong Chol is the first North Korean dignitary in nearly two decades to spend the night in Washington, staying at a fashionable hotel a short drive from the White House.

Secretary of State Mike Pompeo welcomed Kim at the hotel, posing briefly for pictures near a shelf with a framed portrait of civil rights icon Martin Luther King Jr. before a morning meeting.

Pompeo, who traveled to North Korea four times last year to seek progress, later invited the visitors to lunch at their hotel after they returned from the White House.

Trump has repeatedly voiced eagerness to see Kim Jong Un again -- even opining that the two are "in love" after their Singapore summit, the first meeting ever between sitting leaders from the two countries, which never formally ended the 1950-53 Korean War.

Tensions began to abate a year ago with the encouragement of South Korea's dovish president, Moon Jae-in.

Trump has repeatedly hailed his own diplomacy as a triumph, recently saying there would have been "a nice big fat war in Asia" if it were not for his efforts.

- Vietnam ready to host -

In Vietnam, a government source told AFP that "logistical preparations" were under way to host the summit, most likely in the capital Hanoi or coastal city of Danang, but that no decision had been made.

Prime Minister Nguyen Xuan Phuc said that Vietnam was ready to welcome the two leaders, noting that Hanoi has a growing relationship with the United States despite lingering memories of war.

"We don't know the final decision. However, if it happens here, we will do our best to facilitate the meeting," he said in an interview with Bloomberg TV.

For Trump, the made-for-television summitry with the young and elusive North Korean leader would also offer a welcome respite from a steady barrage of negative headlines at home.

An explosive report late Thursday in BuzzFeed said that Trump ordered his lawyer to lie to Congress about a project in Russia, and Trump's insistence that Congress fund a wall on the Mexican border has shuttered the US government for nearly a month.

For Kim, the stakes are more existential as he seeks guarantees of the survival of his regime.

Kim, backed by ally China as well as South Korea, is also hoping for an easing of international sanctions, but the United States insists on maintaining maximum pressure until Pyongyang moves forward on giving up its nuclear weapons.

- Leader-driven diplomacy -

The United States expects Pyongyang to give up its nuclear arsenal, doggedly built by the Kim dynasty through sanctions and famines.

But North Korea sees the denuclearization goal more broadly, seeking an end to what it sees as US threats.

"I think there is somewhat of a general consensus of what denuclearization means. I think there is obviously still disagreement on how to get there -- whether denuclearization is the end of the process or the process itself," said Jenny Town, managing editor of the 38 North web journal on North Korea policy at the Stimson Center.

She noted that Americans have traditionally preferred to hash out the details of agreements before big summits, while the type of leader-driven diplomacy favored by Trump is more common in Asia.

"People have been very skeptical of this top-down approach, but we won't know unless we try it," Town said.