How this story has developed 
 
 - 10 May: Trump says he will meet Kim in Singapore on 12 June 
 
 - 12 May: North Korea announces dismantling of test site 
 
 - 16 May: North threatens to scrap summit over comments by US National Security John Bolton about "Libyan model" 
 
 - 18 May: Trump distances himself from Bolton, saying US is not pushing for Libya-style denuclearisation 
 
 - 22 May: Trump insists that unless the US gets "certain conditions... we won't have the meeting" 
 
 'Careful diplomacy requires careful messaging' 
 
 Analysis from Laura Bicker, BBC News, Seoul 
 
 So we are back to name calling and threats of nuclear war - just weeks before the planned summit. In both cases, Pyongyang was trying to push back against hard-line comments suggesting North Korea may end up like Libya if it doesn't move forward quickly and irreversibly with concrete measures to get rid of its nuclear weapons. "We will neither beg the U.S. for dialogue nor take the trouble to persuade them if they do not want to sit together with us," KCNA quoted her as saying. "Whether the U.S. will meet us at a meeting room or encounter us at nuclear-to-nuclear showdown is entirely dependent upon the decision and behavior of the United States." Trump met with South Korean President Moon Jae-in on Tuesday at the White House for consultations and suggested the summit could be delayed or even called off entirely. "We offered concessions to the North Korean regime in exchange for promises to end their nuclear weapons program, only to see them break those promises and abandon them," Pence said, adding that if Pyongyang does not go along with talks to give up its nuclear weapons, Washington could return to the "Libya model." Photo: Getty Images 
 
 North Korea’s senior envoy for U.S. affairs renewed a threat to call off a planned summit with President Donald Trump and warned that Pyongyang could “make the U.S. taste an appalling tragedy it has neither experienced nor even imagined.” 
 
 In its most direct language aimed at Washington following a recent rapprochement between the two countries, Choe Son Hui, the North’s vice minister of foreign affairs, said if the June 12 talks were called off, the U.S. could instead face off with North Korea in a “nuclear-to-nuclear showdown.” 
 
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– The US has a simple choice, according to Pyongyang: Meet North Korea at the negotiating table, or in a "nuclear-to-nuclear showdown." Senior North Korean official Choe Son Hui put the planned June 12 summit between President Trump and Kim Jong Un in even more doubt Thursday with a blistering statement that warned Pyongyang wouldn't "beg" for dialogue and called Mike Pence a "political dummy," the Wall Street Journal reports. Choe, the North's vice minister of foreign affairs, slammed Pence for comparing North Korea to Libya in the context of denuclearization. "I cannot suppress my surprise at such ignorant and stupid remarks gushing out from the mouth of the US vice president," she said. Choe—who warned that Pyongyang could make the US "taste an appalling tragedy it has neither experienced nor even imagined"—was responding to Pence's comment to Fox News earlier this week, in which he said the Clinton and Obama administrations had been "played" by North Korea and it would be a mistake for the Koreans to think they could do the same to Trump, the AP reports. The BBC notes that Choe is one of Kim's top aides and her statements will have been sanctioned by the leader. Trump said Tuesday that the summit "may not work out" for June 12, but he sounded more optimistic Wednesday, before Choe's remarks were released. "Right now we're looking at it, we're talking about it, and they’re talking to us," he told Fox. "We have certain conditions. We'll see what happens. But there's a good chance."