WASHINGTON (WASHINGTON POST, REUTERS) - CIA Director Mike Pompeo made a top-secret visit to North Korea over the Easter weekend as an envoy for President Donald Trump to meet the country's leader, Mr Kim Jong Un, said Mr Trump on Wednesday (April 18).

The extraordinary meeting between one of Mr Trump's most trusted emissaries and the authoritarian head of a rogue state was part of an effort to lay the groundwork for direct talks between Mr Trump and Mr Kim on North Korea's nuclear weapons programme, according to the two people, who requested anonymity because of the highly classified nature of the talks.

"Mike Pompeo met with Kim Jong Un in North Korea last week. Meeting went very smoothly and a good relationship was formed. Details of Summit are being worked out now. Denuclearization will be a great thing for World, but also for North Korea!" Mr Trump said on Twitter on Wednesday.

The clandestine mission, which has not previously been reported, came soon after Mr Pompeo was nominated to be secretary of state.

"I'm optimistic that the United States government can set the conditions.... so that the President and the North Korean leader can have that conversation that will set us down the course of achieving a diplomatic outcome that America so desperately - America and the world so desperately need," Mr Pompeo told the Senate Foreign Relations Committee last week during his confirmation hearing.

Mr Pompeo has taken the lead in the administration's negotiations with Pyongyang. His meeting with Mr Kim marks the highest level meeting between the two countries since 2000, when then-Secretary of State Madeleine Albright met Mr Kim Jong Il, the current leader's father, to discuss strategic issues.

Director of National Intelligence James Clapper Jr visited the country in 2014 to secure the release of two American captives and met a lower-level intelligence official.

The CIA declined to comment.

Mr Pompeo's visit to the North was arranged by South Korean intelligence chief Suh Hoon with his North Korean counterpart, Kim Yong Chol, and was intended to assess whether Mr Kim was prepared to hold serious talks, a US official said.

Mr Pompeo flew from the US air force base in Osan, south of Seoul, an official with the South's defence ministry said.

The South's presidential office declined to comment on the trip. The White House also declined to comment, saying it would not discuss the CIA director's travels.

The North Korean government also declined to comment.

About a week after Mr Pompeo's trip to North Korea, US officials said that officials there had directly confirmed that Mr Kim was willing to negotiate potential denuclearisation, according to administration officials, a sign that both sides had opened a new communications channel ahead of the summit meeting and that the administration believed North Korea was serious about holding a summit.

"We have had direct talks at very high levels, extremely high levels with North Korea," Mr Trump said on Tuesday during a bilateral meeting with Japanese Prime Minister Shinzo Abe at Mar-a-Lago, his resort.

The United States has no diplomatic relations with North Korea, but US diplomats have visited and Washington has used several quiet channels to communicate with Pyongyang.

"North Korea is coming along," Mr Trump said. "South Korea is meeting and has plans to meet to see if they can end the war, and they have my blessing on that."

Opening a two-day summit with Mr Abe, Mr Trump took some credit for the rapid developments related to North Korea, whose nuclear and ballistic missile tests his administration has considered the gravest national security threat to the United States.

Mr Trump said that South Korean officials have "been very generous that without us, and without me in particular, I guess, they wouldn't be discussing anything and the Olympics would have been a failure".

Seoul used the Winter Games, held in Pyeongchang in February, as a vehicle to reopen diplomatic talks with Pyongyang.

North Korea sent athletes and a high-level delegation to the event in a major sign of warming relations with South Korea, a US ally.

That has led to a flurry of high-stakes diplomacy in East Asia, in which Mr Trump has seized a leading role.

"There's a great chance to solve a world problem," Mr Trump said. "This is not a problem for the United States. This is not a problem for Japan or any other country. This is a problem for the world."

Hostilities in the Korean War, which involved the United States, ended 65 years ago, but a peace treaty was never signed.

A top South Korean official was quoted on Tuesday as saying that a formal end to hostilities was on the agenda for the summit between Mr Kim and South Korean President Moon Jae In next week in the demilitarised zone between the countries.

"They do have my blessing to discuss the end of the war," Mr Trump said.

Yet such a deal would be complicated and would require direct US participation and agreement.

The United States signed the armistice agreement on South Korea's behalf, and any peace treaty would have to be between the United States and North Korea.

A big part of the reason a peace treaty has never been signed is that Pyongyang has long insisted that if a peace treaty was agreed, US troops would no longer be required in South Korea, a demand the United States has rejected.

Mr Trump's planned session with Mr Kim, the dynastic leader Mr Trump has mocked as "Little Rocket Man", comes after the two traded insults and threats last year.

Mr Trump vowed to "totally destroy" North Korea if it menaced the United States or its allies, and Mr Kim called Mr Trump senile.

On Tuesday, Mr Trump said the summit with Mr Kim was likely to happen by early June, if all goes well.

He added a caveat: "It's possible things won't go well and we won't have the meetings and we'll just continue to go on this very strong path we have taken."

Mr Trump later said that five locations are under consideration to host the summit and that a decision would come soon.

None of the locations was in the US, Mr Trump said later, in response to a question from a reporter.

Administration officials are said to be looking at potential sites in Asia outside the Korean peninsula, including South-east Asia, and in Europe.

Mr Abe appeared delighted with the progress he made with Mr Trump, including a pledge from the US President to raise with Mr Kim the issue of the unresolved cases of at least 13 Japanese citizens abducted by North Korean agents in the 1970s and 1980s - an important domestic issue for Mr Abe.

Mr Trump met several families of the abductees during a visit to Tokyo in November, and the President was outraged by the death last summer of Mr Otto Warmbier, an American college student who died shortly after being released in a coma from 17 months in captivity in the North.

Three Americans remain in captivity, and US officials suggested their release is likely to be part of talks with Pyongyang.

"This reflects your deep understanding for how Japan cares about this abduction issues. I am very grateful for your commitment," said Mr Abe, who also pressed Mr Trump to maintain "maximum pressure" on Pyongyang.

Mr Trump and Mr Abe entered their summit hoping to repair a relationship that has been strained by Mr Trump's decisions to meet Mr Kim, which has alarmed Tokyo, and his move to enact steel and aluminium tariffs without granting Japan a waiver.

In a sign that the two leaders were aiming to recreate their early chemistry, Mr Trump said the two would sneak out for a round of golf on Wednesday ahead of additional meetings.

The President referred, as he has before, to Mar-a-Lago as the "winter White House".

Trump aides acknowledged that they are probing the possibility of the United States re-entering the 11-nation Trans-Pacific Partnership, but emphasised that such a move is premature.

Mr Larry Kudlow, Mr Trump's chief economic adviser, played down a rift with Japan on trade and said the administration's tariffs were aimed at punishing China, which he accused of "acting like a third-world economy".

Mr Kudlow declared that a global coalition stands behind the Trump administration's strategy.

"This trade coalition of the willing that I've been talking about, that others have been talking about, is really aimed at China," he said. "China is a first-world economy behaving like a third-world economy. And with respect to technology and other matters, they have to start playing by the rules."

The US does not need the TPP to confront Chinese bad behaviour, Mr Kudlow said.

He touted a strong US economy as leverage for American ideas on trade around the world and said Mr Trump's tougher stance on Chinese trade has won wide international backing.

"The rest of the world is with us. The President hasn't consciously sought this, but it's happening, and it's a good thing," Mr Kudlow said. "So I hope China reads that carefully and responds positively."

China on Tuesday announced temporary anti-dumping measures targeting US sorghum, potentially hitting growers in states such as Kansas and Texas that Mr Trump won in the 2016 election.

The move discouraging imports of US sorghum widens the brewing trade war between Beijing and Washington.

On Monday, the US banned US firms from selling parts to Chinese phone maker ZTE for seven years, as the world's two largest economies continue to exchange threats of tariffs worth billions of dollars.

But Mr Trump sought to balance his aides' criticism of Beijing with praise for Chinese President Xi Jinping, whom Mr Trump has pressed to enact economic sanctions on North Korea.

"He's been incredibly generous," Mr Trump said. "President Xi has been very strong on the border, much stronger than anyone thought they would be. I'd like them to be stronger on the border, but he's been at a level nobody ever expected. The goods coming into North Korea have been cut down very substantially."