North Korean leader Kim Jong Un has arrived in Vietnam for a second summit with US President Donald Trump, where they will try to reach an agreement on a North Korean pledge to give up its nuclear weapon programme.
Mr Trump is due to arrive in the Vietnamese capital, Hanoi, later today.
Mr Trump will meet Mr Kim for a brief one-on-one conversation on tomorrow, followed by a social dinner, at which they will each be accompanied by two guests and interpreters, White House spokeswoman Sarah Sanders said.
She said that would be followed by more meetings between the two leaders on Thursday.
Their talks come eight months after their historic summit in Singapore, the first between a sitting US president and a North Korean leader.
While there is no real expectation that the second meeting will bring a final deal on ridding North Korea of nuclear weapons that threaten the United States, there are some hopes it could lead to a declaration that the 1950-53 Korean War is at last formally over.
But the United States would expect significant movement by Mr Kim towards denuclearisation in return.
In Singapore, Mr Kim pledged to work toward complete denuclearisation of the Korean peninsula, but the vague agreement struck there has produced few concrete results.
US Democratic senators and security officials have warned Mr Trump against cutting a deal that would do little to curb North Korea's nuclear ambitions.
Mr Kim, who travelled from the North Korean capital by train, arrived at the station in the Vietnamese town of Dong Dang after crossing over the border from China.
Vietnamese officials were on hand to welcome him with a red-carpet including a guard of honour and North Korean and Vietnamese flags flying.
Mr Kim left the train in Dong Dang and got into a Mercedes Benz vehicle for the 170km journey to the capital, Hanoi, by car.
He waved from the car before setting off to young people lining the street waving Vietnamese and North Korean flags.
About a dozen body guards ran along side his car as he set off.
The main road into Hanoi was closed off with Vietnamese security forces equipped with armoured-personnel carriers guarded the route.
Both leaders are also due to hold separate talks with Vietnamese leaders.
US Secretary of State Mike Pompeo also arrived in Hanoi, on Tuesday, a reporter travelling with him said.
Mr Pompeo has been Mr Trump's top envoy in his efforts to improve ties with the reclusive North and has made several trips to Pyongyang to negotiate steps towards ending its nuclear programme.
Mr Pompeo was due to met US Special Representative for North Korea Stephen Biegun in Hanoi later.
Trump expects 'a very tremendous summit'
Mr Trump told reporters he and Mr Kim would have "a very tremendous summit".
Tweeting earlier this week, he stressed the benefits to North Korea if it gave up its nuclear weapons.
"With complete Denuclearization, North Korea will rapidly become an Economic Powerhouse. Without it, just more of the same. Chairman Kim will make a wise decision!" Mr Trump said.
In a speech on Sunday night, Mr Trump, however, appeared to play down any hope of a major breakthrough at the Hanoi summit, saying he would be happy as long as North Korea maintained its pause on weapons testing.
"I'm not in a rush. I don't want to rush anybody," he said. "I just don't want testing. As long as there's no testing, we're happy."
North Korea conducted its last nuclear test in September 2017 and last tested an intercontinental ballistic missile in November 2017.
A South Korean presidential spokesman told reporters in Seoul that the two sides might be able to agree to a formal end of the Korean War, which ended in an armistice not a peace treaty, a move North Korea has long sought.
While a formal peace treaty may be a long way off, the two sides have discussed the possibility of a political declaration stating that the war over.
"The possibility is there," South Korean spokesman Kim Eui-kyeom told a briefing.