CIA director Mike Pompeo travelled to Pyongyang for a secret meeting with North Korean leader Kim Jong-un, US media report.
The meeting to prepare for direct talks between US President Donald Trump and Mr Kim took place over Easter weekend, unnamed officials said.
Mr Trump had earlier alluded to high-level direct talks with Pyongyang.
But this unexpected and clandestine meeting would mark the highest level US contact with North Korea since 2000.
“We have had direct talks at… extremely high levels,” Mr Trump said from Florida, where he is hosting Japan’s Prime Minister Shinzo Abe.
The president added that he gave his “blessing” for talks between the South and North to discuss a peace treaty to formally end the 1950-1953 Korean War.
South Korea has also signalled that it may pursue a formal resolution of the conflict. South Korea’s President Moon Jae-in and Mr Kim are scheduled to meet at the end of April.
What do we know about the ‘secret meeting’?
The news that Donald Trump’s nominee for US Secretary of State had travelled to North Korea for a clandestine meeting with Mr Kim was first reported by The Washington Post newspaper.
Very little is known about the talks other than that they were to prepare for the upcoming Trump-Kim summit.
According to the paper, the meeting took place soon after Mr Pompeo was nominated as secretary of state and is attributed to two anonymous sources “with direct knowledge of the trip”.
Later the Reuters news agency said the report had been confirmed to them by senior officials.
The White House has not commented.
How do the US and North Korea communicate?
The US does not have diplomatic relations with North Korea, although diplomats have visited in the past and there are some so-called “back channels” used to communicate with Pyongyang.
Mr Pompeo’s trip was the highest level meeting with a North Korean leader since 2000 when then-Secretary of State Madeleine Albright met Kim Jong-il, the father of the current leader, in Pyongyang.
In 2014, the then-head of National Intelligence James Clapper visited North Korea in a secret mission to negotiate the release of two US citizens. Mr Clapper did not meet the North Korean leader during his trip.