The United States has had contacts at the highest levels with North Korea but Donald Trump and Kim Jong Un have not spoken directly, the White House said late on Tuesday.

The Washington Post reported that CIA chief Mike Pompeo made a secret visit to Pyongyang over the first weekend of April and met with Kim.

The meeting was part of an effort to prepare for a historic meeting in the coming weeks between Trump and Kim, the paper said, quoting two people with direct knowledge of the trip.

The visit came shortly after Pompeo was nominated to be secretary of state.

Both the White House and the CIA declined to comment on the report.

White House spokeswoman Sarah Sanders clarified earlier comments by Trump, who appeared to answer “yes” to a question shouted by a reporter as to whether he had already spoken with Kim.

“The president said the administration has had talks at the highest levels and added that they were not with him directly,” Sanders said.

Trump, in Florida hosting Prime Minister Shinzo Abe of Japan, confirmed direct contacts between the United States and North Korea. He gave his blessing to discussions aimed at formally ending the Korean war.

Setting the stage for a major breakthrough at a series of upcoming summits, Trump said “a great chance to solve a world problem” was within reach on the Korean peninsula.

Side-by-side with Abe at Trump's Palm Beach, Florida resort, the US president said that a rare inter-Korean summit later this month could, with his “blessing,” discuss an elusive peace treaty.

Trump confirmed that Washington and Pyongyang had been in contact at “very high levels” and that “five locations” were being considered for his meeting with Kim.