Trump, who has struck a decidedly optimistic tone on the situation in recent days, said Tuesday that the United States and North Korea were having “good discussions”.

“We have been told directly that they would like to have the meeting as soon as possible. We think that’s a great thing for the world,” Trump said at the White House alongside French President Emmanuel Macron. “Kim Jong-un, he really has been very open and I think very honourable from everything we’re seeing.”

Trump cautioned that North Korea had not followed through on previous promises, but credited tough steps from his administration – including sanctions and organising pressure from international allies – for having forced Pyongyang to hold talks. 

And he again suggested that he would “leave the table” if the negotiations were not productive or if North Korea was not operating in good faith.

“We’ll see where that all goes,” Trump said. “Maybe it will be wonderful or maybe it won’t.”

His comments came days after a flurry of signs from North Korea that the White House was anxious to promote as signs that its coercion campaign was working.

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On Saturday, North Korea announced that it would close its nuclear testing facility and suspend nuclear and intercontinental ballistic missile tests – a move welcomed by Trump as “big progress”.

However, the North stopped short of suggesting it would give up its nuclear weapons – as Trump suggested in a tweet – or scale back its production of missiles and their related components.

Asked if the suspension of tests was a positive sign, Defence Secretary Jim Mattis said Monday, “Right now, I think there (are) a lot of reasons for optimism that the negotiations will be fruitful, and we’ll see.”

This week, US-allied South Korean President Moon Jae-in and Kim are scheduled to hold a summit in the demilitarised zone between the Koreas that could lay the ground for Trump’s planned meeting with the North Korean dictator. 

The leaders of the US and North Korea have never met in the more than six decades since the Korean war. The exact date and location of the possible summit has not been determined.

White House press secretary Sarah Huckabee Sanders said Monday that the US goal was the complete denuclearisation of the Korean peninsula. When asked if the president was willing to accept anything short of that goal before lifting sanctions or was willing to go incrementally, she told reporters: “Certainly no sanctions lifted until we see concrete actions taken by North Korea to denuclearise.”

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Last year, the US pushed through the UN Security Council the toughest international sanctions yet against North Korea in response to three long-range missile launches and its most powerful nuclear test explosion to date. 

The Trump administration supplemented those restrictions with unilateral US sanctions against firms that had conducted illicit trade with the North.

This year, Kim has moved from confrontation to diplomacy and, according to South Korea and China, has expressed a commitment to denuclearisation. 

There is still uncertainty about what he seeks in return.

Trump’s praise for Kim Jong-un on Tuesday stood in stark contrast to his previous bellicose rhetoric toward him. 

Beyond calling him “Little Rocket Man” from the rostrum of the United Nations last fall, Trump has threatened to deliver “fire and fury” upon North Korea and taunted Kim on Twitter that his nuclear “button” was larger than the one in Pyongyang.