Donald Trump's most senior expert on weapons of mass destruction is with him in Singapore for tomorrow's historic summit, the US has revealed, as it admitted it has been "fooled before" by North Korea.

US Secretary of State Mike Pompeo said the president will be going into the face-to-face talks with "confidence" and a "positive attitude", but his "ultimate objective" remained unchanged and "complete verifiable and irreversible" denuclearisation was the only outcome America will accept.

:: Your guide to the Trump-Kim summit

Pompeo: 'US has been fooled before'

In return, he said, "we will take actions to provide them sufficient certainty that they can be comfortable that denuclearisation is not something that ends badly for them".

"Just the opposite. That it leads to a brighter and better future for the North Korean people."


:: Why the eyes of the world are on Trump-Kim summit

Speaking on the eve of the much anticipated encounter, Mr Pompeo said these guarantees would be "different and unique" than the US has been willing to provide before.

The summit provides "an unprecedented opportunity to change the trajectory of our relationship and bring peace and prosperity" to North Korea, he said.

Responding to a report in The New York Times that the US lacks the technical expertise on dismantling North Korea's weapons programme, Mr Pompeo said more than 100 experts on nuclear, chemical, biological and missile warfare had been working on the logistics of the issue for the past three months.

Korea: A divided history

"On the ground in Singapore, we have a team that includes the president's most senior expert in weapons of mass destruction, who can cover any technical needs that the meetings may present," he said.

Mr Trump has said he will "know within the first minute" if North Korean leader Kim Jong Un is serious about giving up his nuclear arsenal in return for diplomatic and economic incentives.

:: What does Kim really want?

Soon after his arrival in Singapore he tweeted on the eve of the summit: "Great to be in Singapore, excitement in the air!"

Great to be in Singapore, excitement in the air! — Donald J. Trump (@realDonaldTrump) June 11, 2018

Mr Pompeo, who has been instrumental in setting up the first ever meeting between a US and North Korean leader, sounded an upbeat tone and said preparatory talks were "moving quite rapidly".

He said Mr Trump was "fully prepared" and was optimistic that the outcome would be "successful", while warning that there was still "lots of work left to do".

"The United States has been fooled before," said Mr Pompeo.

What does North Korea really want?

"We are going to ensure that we set up a system sufficiently robust that we are able to verify these outcomes... that's what's been missed before.

"We will each have to ensure that we do the things, we take the actions necessary to follow through on those commitments, and when we do we will have a verified deal. If we can get that far we will have had a historic change."

"I'm very optimistic we will have a successful outcome with the two leaders," he said.

"There are only two people that can make decisions of this magnitude, and those two people are going to be sitting in a room tomorrow."

Earlier, during a working lunch with Singapore's Prime Minister Lee Hsien Loong, Mr Trump said his meeting with Mr Kim could "work out very nicely" as behind-the-scenes talks continued between officials from both countries.

Image: Donald Trump blows out the candle on his birthday cake

Parties from both sides tucked into Lobster bisque, beef tenderloin and ice cream - and there was an additional surprise dessert, as Mr Trump, who turns 72 on Thursday, was presented with an early birthday cake.

Mr Trump arrived aboard Air Force One just a few hours after Mr Kim, who has only publicly left his country three times since taking power in 2011.

The pair are staying in hotels - the president at the Shangri-La and the North Korean leader at the St Regis Hotel - which are situated less than a brisk 10-minute walk apart ahead of their meeting at the Capella Hotel on the Singaporean resort island of Sentosa.