US president Donald Trump has declared there is “no longer a nuclear threat from North Korea” following his ground-breaking summit with Kim Jong Un in Singapore.

While no guarantees were produced at the summit over how or when Pyongyang would disarm, US secretary of state Mike Pompeo warned that the US would resume military exercises with South Korea if the North stops negotiating in good faith.

This came after Mr Trump announced a halt in the drills after his meeting with North Korean leader Mr Kim.

Donald TrumpMr Trump’s upbeat assessment was tempered by Mike Pompeo’s comments (AP)

Mr Pompeo also said the US wants North Korea to take “major” nuclear disarmament steps before the end of Mr Trump’s first term in 2021.

The summit in Singapore, which marked a major reduction in tensions, yielded a joint statement that contained a promise to work toward a denuclearised Korean Peninsula, but it lacked details.

This did not stop the US president from talking up the outcome of what was the first meeting between a US and North Korean leader in six decades of hostility. The Korean War ended in 1953 without a peace treaty, leaving the two sides in a technical state of war.

Mr Trump tweeted: “Just landed – a long trip, but everybody can now feel much safer than the day I took office.

“There is no longer a Nuclear Threat from North Korea. Meeting with Kim Jong Un was an interesting and very positive experience. North Korea has great potential for the future!”

However Mr Pompeo, who flew to Seoul to brief South Korean leaders on the summit, said the North Korean leader understands that “there will be in-depth verification” of nuclear commitments in any deal with the US.

While the US leader was facing questions at home and among allies about whether he gave away too much in return for far too little at the summit, North Korean state media heralded claims of a victorious meeting with the US president. Images of Mr Kim standing side-by-side with Mr Trump on the world stage were splashed across newspapers.

Mr Trump’s claim that North Korea no longer poses a nuclear threat is questionable considering Pyongyang’s significant weapons arsenal.

Independent experts say the North could have enough fissile material for anywhere between about a dozen and 60 nuclear bombs.

Last year it tested long-range missiles that could reach the US mainland, although it remains unclear if the regime has mastered the technology to deliver a nuclear warhead that could re-enter the atmosphere and hit its target.

When asked whether Mr Trump was jumping the gun by declaring victory, White House adviser Kellyanne Conway told reporters: “This president wants North Korea to completely denuclearize so obviously that has to be complete, verifiable and irreversible.”