With the meeting between Donald Trump and Kim Jong-un on the rocks, North Korea has issued a statement saying the US must decide if it wants a meeting or a nuclear showdown.
The reclusive state said the United States must decide whether it wants to "meet us at a meeting or encounter us at nuclear-to-nuclear showdown," The Washington Post reported, after the US President suggested the historic summit might be postponed.
Donald Trump said on Tuesday there is a strong chance his summit with Kim Jong-un planned to take place in Singapore on June 12 will not go ahead, amid concerns the North Korean leader is not committed to denuclearisation.
"If it doesn't happen, maybe it will happen later," Mr Trump said.
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Mr Trump was responding to an abrupt change in tone from North Korea last week, when Pyongyang suggested the summit could be cancelled if North Korea was pushed toward "unilateral nuclear abandonment".
Now, US Vice President Mike Pence may have made the situation worse by comparing North Korea to Libya while speaking to US media.
"As the President made clear, this will only end like the Libyan model ended if Kim Jong-un doesn't make a deal," Mr Pence told Fox News, referring to former Libyan leader Muammar Gaddafi.
Gaddafi gave up his nuclear weapons programme in 2003 in exchange for sanctions relief, but was soon overthrown and killed in 2011.
A close aide of Kim Jong-un's, Choe Son Hui, has labelled Mr Pence a "political dummy" for his comments.
The vice-foreign minister, who was once the North Korean regime's leading official in charge of relations with the US, added he "cannot supress my surprise at such ignorant and stupid remarks".
Asked whether New Zealand should be worried about the relationship between North Korea and the US souring once again, University of Otago foreign policy lecturer James Flynn told Newshub he doesn't see any reason why it should have a direct impact on us.
But nations that are close to North Korea and have a history of animosity with the reclusive state, such as Japan, might fear North Korea's nuclear weapons and feel like they need them too - particularly if the US is unable to convince North Korea to end its nuclear programme.
But Professor Flynn said he rejects the idea that North Koreans are crazy, and will use their nuclear weapons for any reason.
"They're not lunatics running around," he said. "I don't think New Zealand should feel threatened by North Korea."
He said he cannot understand why the meeting between Donald Trump and Kim Jong-un was ever considered a done deal in the first place.
Mr Flynn said Kim Jong-un would be risking a lot by telling his people that all the money he spent on nuclear arms was a waste and that America is not as wicked as he once said it was.
"That would be highly embarrassing," he said.
In a statement released by North Korea's official Korea Central News Agency, Ms Choe said if the United States "offends against our goodwill and clings to unlawful and outrageous acts," she would suggest Kim reconsider the summit with Donald Trump.
"Whether the US will meet us at a meeting room or encounter us at nuclear-to-nuclear showdown is entirely dependent upon the decision... of the US," she said.
While remaining committed to the summit, President Trump has privately wondered whether North Korea is serious about denuclearising, a senior US official said.