Trump, who had once suggested inviting Kim over for a hamburger to persuade him to give up his nuclear weapons program, took to his usual medium to respond.
But how, experts asked, did the U.S. president-elect aim to stop it happening?
The head of the Brookings Institution offered one interpretation.
South Korea, not wanting perhaps to contemplate that possibility of rockets raining down on the Korean Peninsula, took a different view. Its Foreign Ministry said Trump in his tweet had issued a “clear warning” to North Korea that showed his awareness of the urgency of the threat — and that he will not waver from a policy of imposing sanctions.
“Because of our active outreach, President-elect Trump and U.S. officials are clearly aware of the gravity and urgency of the North Korean nuclear threat,” ministry spokesman Cho June-hyuck told a briefing. “They are maintaining an unwavering stance on the need for sanctions on North Korea and for close cooperation between South Korea and the U.S.”
This also raises the issue of how much interpretation should be required for the tweets of what will soon be the most powerful man in the world.
Euan Graham, director of the international security program at the Lowy Institute in Sydney, said the world was “on the slippery slope of trying to interpret one man’s not particularly coherent tweets.” But he added that the exchange has increased the chances that North Korea could be “the first crisis out of the box” in the Trump presidency, at least in Asia.
Certainly Trump does appear to be concerned about the issue.
Citing a senior U.S. intelligence official, Reuters reported that Trump's first, and at that time only, request for a special classified intelligence briefing was for one on North Korea and its nuclear weapons program. Obama also reportedly made clear his concerns over the issue at his handover conversation with Trump.
But what is Trump going to do? His next tweet offered a clue. Get China to do more.
Those comments did not go down particularly well in Beijing, which argued it had been long pushing for the denuclearization of the Korean Peninsula, and cast itself as the voice of reason and moderation.
“China’s efforts in this regard are perfectly obvious,” Foreign Ministry spokesman Geng Shuang told a regular news conference. “As a permanent member of the U.N. Security Council, we have proactively participated in relevant discussions on the North Korean nuclear issue and have jointly passed several resolutions with other parties.
“This shows China’s responsible attitude.”
China’s nationalist Global Times newspaper took the argument a stage further, saying that Trump was “pandering to irresponsible attitudes” and “stoking the anxieties of some Americans” in his accusations against China.
Chinese foreign policy experts say the United States was wrong to blame their country, arguing that the fundamental motivation for North Korea, formally known as the Democratic People's Republic of Korea or DPRK, to develop nuclear weapons is American “hostility.”
“The DPRK feels unsafe because the United States wants to overthrow it,” said Cai Jian, a professor of Korea studies at Fudan University in Shanghai. “Now the United States blames China and believes China is irresponsible. This is very ridiculous.”
The United States has long insisted that North Korea must disarm before talks can be held, and has responded to the country’s nuclear and missile tests by tightening sanctions. The latest round was imposed by the U.N. Security Council in November and supported by China.
But despite the sanctions, data shows trade between China and North Korea is still growing, said Graham.
Kim has put North Korea’s nuclear weapons policy at the center of his country’s national and security strategy. China would like Pyongyang to abandon the program, but is unwilling to do anything that might destabilize the regime, Western experts say.
Frustration with China over the issue is something Trump shares with all of his immediate predecessors, Graham said, but the president-elect’s generally hard line toward Beijing would only make it “dig in its heels” more firmly, he said.
Meanwhile, Trump’s brash style has been something of a propaganda gift for Beijing.
“There’s a funny sort of inversion game going on there,” Graham said. “China is trying to posture as the global stakeholder and the reliable party for regional peace and global governance, whereas the United States is, in China’s eyes, reeling around like a punch-drunk heavyweight.”
Jin Xin contributed to this report.