“We’re going to see a confrontation between the United States and North Korea that will be ferocious and strong and bloody,” said Cheng Xiaohe, an associate professor of international relations at Renmin University of China in Beijing who called Mr. Trump’s language “explosive.”
Professor Cheng said he was puzzled by the timing of Mr. Trump’s remark, just days after the United Nations Security Council imposed the toughest economic penalties yet on North Korea for its nuclear and missile programs. That unanimous vote, which overcame China’s historical reluctance to punish its ally harshly, has been widely described as the Trump administration’s greatest diplomatic accomplishment so far.
“Usually, the U.S. government is willing to give more time for a resolution, to see how the resolutions bite,” Professor Cheng said.
Across the region on Wednesday, analysts reacted with concern and even foreboding about the tone of Mr. Trump’s comments, and about the unimpeded progress that North Korea appears to be making toward becoming a full-fledged nuclear power, able to strike the United States or other far-off adversaries.
While Mr. Trump’s warning that North Korea, if it kept threatening the United States, would “be met with fire and fury like the world has never seen” clearly reflected growing American frustration over the North’s advances, analysts said it was not clear that he had fully considered the implications of such strong language.
That, they said, raised questions about the administration’s strategy, and about whether Mr. Trump recognized the price that some staunch allies, especially Japan and South Korea, could pay for carrying out his threat.
“Trump doesn’t seem to understand what an alliance is, and doesn’t seem to consider his ally when he says those things,” said Lee Byong-chul, a senior fellow at the Institute for Peace and Cooperation in Seoul, South Korea’s capital. “No American president has mentioned a military option so easily, so offhandedly as he has. He unnerves people in South Korea, few of whom want war in Korea.”
Mr. Trump’s warning followed a report that American intelligence agencies believe that North Korea has made a nuclear weapon that can fit on the tip of a ballistic missile. Such drastic advances have already led Japan and South Korea to consider deploying new, more powerful weapons to counter the threat, after decades of relying on American military might for strategic security.
Itsunori Onodera, Japan’s new defense minister, said Wednesday that Japan found it credible that North Korea had succeeded in miniaturizing a nuclear warhead, or that it would do so in the near future. “At the very least, whether they have them now or will have them soon, it’s reached a level where we have to monitor vigilantly,” he said.
Officials in Asia and beyond have grown used to provocative musings by Mr. Trump, particularly on Twitter, and they tend to treat them as inaccurate reflections of American policy. But analysts saw his “fire and fury” remark as dangerous and unlikely to deter North Korea’s leader.
“We are used to painting North Korea as ‘unpredictable,’ but increasingly it is the U.S. that is introducing strategic unpredictability into a volatile dynamic,” Euan Graham, an analyst at the Lowy Institute in Sydney, Australia, wrote in an email.
Professor Cheng of Renmin University said that North Korea’s defiance in response to the Security Council’s latest sanctions indicated that it had no intention of slowing its program. He said that nations across the region, including his own, needed to prepare for the consequences of a conflict.
“We are in a very dangerous time, and China is going to need to take notice and prepare for the worst,” he said.
China’s Foreign Ministry, responding Wednesday to an inquiry about Mr. Trump’s threat, restated its position that the North Korean nuclear issue should be resolved by political means and that “all relevant parties” should avoid “remarks and acts that may escalate the conflict.”
The South Korean government sought on Wednesday to ease concern, saying that the North’s recent posturing, including its threat to attack Guam, appeared to be aimed at tightening solidarity among its own population and causing its neighbors anxiety.
“The situation has become more serious on the Korean Peninsula,” a senior official at the presidential Blue House told South Korean reporters, speaking in a briefing on the condition of anonymity. “But we don’t think it has reached a crisis stage yet.”
Also on Wednesday, Pyongyang released a Canadian pastor, the Rev. Lim Hyeon-Soo, who had been sentenced to a life of hard labor. Nearly two months ago another former prisoner, Otto F. Warmbier, an American college student, died after being freed.
“North Korea appears to signal that it could be flexible amid this standoff with the international community,” said Kim Yong-hyun, a professor of North Korean studies at Dongguk University in Seoul. He added that the freed pastor is Canadian, “so the North may find it easier to release him” than to be perceived as capitulating to a bellicose American president.
In Japan, a senior government official sought to frame Mr. Trump’s remark as an effort to warn the North’s government that military action remained a possibility, even as the new sanctions begin going into effect.