North Korea is reportedly ready to negotiate over its nuclear programme with the United States following historic peace talks with South Korea this week.
According to South Korea officials, Kim Jong-un would agree to temporarily stop nuclear tests if US holds talks with the regime.
Donald Trump said there was “possible progress” but warned the talks, which were attended by Kim and his wife and sister, could be “false hope”.
Speaking on Fox News, the former US ambassador said South Korea is like “putty in North Korea’s hands” as he warned the talks are only an effort to prolong further sanctions.
He said: “It’s very emotional for South Koreans, I understand it. But as the great international relations theorist P.T. Barnum once said, there’s a sucker born every minute.”
Mr Bolton demanded America should not let Kim Jong-un get to the point in which he is capable of striking the US with nuclear weapons.
He said: “I don’t think we should let them get to that point and that prediction is based in part on what CIA director Mike Pompeo has been saying that they are within a handful of months of being able to hit targets in the United States.
“I think if they get nuclear weapons they are a threat in East Asia.”
The former US ambassador said the talks are a “temporary device” by North Koreans to buy time to make progress on its nuclear programme. He warned: “They made not need to have any more nuclear tests, that’s what the freeze proposal may mean. Now they may just be manufacturing nuclear devices.”
He added: “Any prospect of actually finding out what they are up to would have to be so intrusive, so large, so pervasive across the country that it would threaten the stability of the dictatorship itself.
“That is one reason among many why it will never happen.”
He said the talks, which excluded US negotiators, were being watched by the entire world but urged caution and sensible expectations.
Mr Trump tweeted on Tuesday: “Possible progress being made in talks with North Korea. For the first time in many years, a serious effort is being made by all parties concerned.
“The world is watching and waiting! May be false hope, but the US is ready to go hard in either direction!”
There was no immediate response from Pyongyang.
North and South Korea are expected to hold their first official summit in more than a decade next month at the border village of Panmunjom.
Seoul delegate Chung Eui-yong said of last night’s meeting: “North Korea made clear its willingness to denuclearise the Korean peninsula and the fact there is no reason for it to have a nuclear programme if military threats against the North are resolved and its regime is secure.
“The North also said it can have frank talks with the United States on denuclearisation and the normalisation of ties between North Korea and the United States.”
The prospect of talks between the isolated North and the United States helped boost global stock markets, with the broadest gauge of global shares, MSCI’s All Country World Index, rising 0.7 percent and Wall Street stocks opening higher.