Donald Trump has warned North Korea to scrap its nuclear weapons programme or face "total decimation", drawing parallels with former Libyan leader Muammar Gaddafi.
North Korea has argued that it needs to keep its nuclear arsenal for security, citing the example of Gaddafi, who died at the hands of rebels in an uprising in October 2011 after giving up his nuclear programme in the 2000s.
The US president said that if North Korean leader Kim Jong Un agreed to denuclearise, he would "get protections that would be very strong".
But failure to do so would have severe consequences, he said.
Mentioning Libya himself, Trump said: "If you look at that model with Gaddafi, that was a total decimation. We went in there to beat him.
"Now that model would take place if we don’t make a deal, most likely."
It also abruptly cancelled a planned meeting with South Korean officials over joint military exercises by the US and South Korea.
Exercise Max Thunder began on Monday and is due to end on May 25.
It includes aircraft from across the US military. A similar exercice last year's exercise involved around 1,200 US personnel and 640 from South Korea.
On Thursday, the regime's mission to the United Nations issued a statement claiming that nuclear-capable B-52 bombers and F-22 fighter planes were taking part, describing it as “an extremely provocative and ill-boding act”.
However, Trump said that despite the threats to call off the meeting, they had been "negotiating like nothing happened”.
Meanwhile South Korea said it too believes North Korea remains committed to improving relations despite the criticism.
South Korea’s Unification Ministry spokesman Baek Tae-hyun said Seoul expects Pyongyang to faithfully abide by the agreements between North Korean leader Kim Jong Un and South Korean president Moon Jae-in in their summit last month.
The Korean leaders had issued a vague vow on the “complete denuclearisation” of the peninsula and pledged permanent peace.
“We are just at the starting point and we will not stop or waver as we move forward for peace in the Korean Peninsula,” said Mr Baek.