Details of a second summit between US president Donald Trump and North Korean leader Kim Jong-un will be announced early next week, Mr Trump said on Thursday, as he hailed "tremendous" progress in talks between the two sides.
Mr Trump said the time and place of the meeting had already been agreed, with the summit scheduled to take place at the end of February.
Vietnam has been mentioned as one possible location for the meeting – a follow-up to the Singapore summit last June that was the first ever face-to-face meeting between the leader of North Korea and a sitting US president.
Mr Trump was speaking a day after he branded the heads of the US intelligence agencies “naive” over their assessments of various foreign policy challenges, including North Korea.
US director of national intelligence Dan Coats told a congressional committee earlier this week that Pyongyang was "unlikely to completely give up its nuclear weapons and production capability" and that the country's leaders "ultimately view nuclear weapons as critical to regime survival".
Asked if he still had confidence in Mr Coats and CIA director Gina Haspel, Mr Trump replied: "Time will prove me right, probably."
Separately, secretary of state Mike Pompeo confirmed that a team of officials was being dispatched to the region to lay preparatory ground for the upcoming summit.
Among them will be US special envoy for North Korea Stephen Biegun, who flies to South Korea on Sunday for meetings with his counterpart, Lee Do-hoon.
Mr Biegun warned on Thursday that Washington had “contingencies” to deal with North Korea if the diplomatic process failed.
In a speech delivered in California, he said Pyongyang must provide a comprehensive declaration of its nuclear and missile programmes and agree to monitoring.
Ultimately, he added, North Korea must ensure the “removal or destruction of stockpiles of fissile material, weapons, missiles, launchers and other weapons of mass destruction”.
As focus began to turn in Washington to Mr Trump's forthcoming meeting with Mr Kim, the president's foreign policy credentials were dealt a further blow on Thursday when the Senate voted to advance legislation opposing the early withdrawal of US troops from Syria and Afghanistan.
The resolution, which was added as an amendment to a larger Middle East policy Bill by Senate majority leader Mitch McConnell, warned that the "precipitous withdrawal" of US forces from Syria and Afghanistan "could put at risk hard-won gains and United States national security".
The measure also stated that the US faces “continuing threats from terrorist groups operating in Syria and Afghanistan”.
Mr Trump announced in December plans to withdraw US troops from Syria, claiming that the Islamic State terror group had been defeated.
The vote was the latest rebuke by Senate Republicans of key elements of Mr Trump's foreign policy. In December the Senate voted to end American military assistance for the war in Yemen, amid widespread concern about the Trump administration's response to the murder of Saudi journalist Jamal Khashoggi.
In addition, eleven Republican senators sided with Democrats last month in calling on the US treasury to reconsider its decision to lift sanctions on energy giant Rusal, a company controlled by Russian oligarch Oleg Deripaska.
Meanwhile as negotiations continued in Congress about reaching a government funding plan to avoid a renewed government shutdown when current spending bills expire on February 15th, Mr Trump reiterated his demands for a Mexican border wall.
“On February 15th the committee will come back and if they don’t have a wall, I don’t even want to waste my time reading what they have because it’s a waste of time,” he said in response to questions from reporters in the Oval Office on Thursday. “Because the only thing that works for security and safety for our country is a wall.”
