BEIJING (NYTIMES) - United States President Donald Trump's threat to unleash "fire and fury" against North Korea sent a shudder through Asia on Wednesday (Aug 9), raising alarm among allies and adversaries and, to some observers, making the possibility of military conflict over the North's nuclear programme seem more real.

With North Korea responding that it would, if attacked, strike US military forces in Guam, analysts warned that the escalating statements increased the likelihood of war - perhaps one based on miscalculation, should one side's fiery rhetoric be misread by the other.

Some played down Trump's remark Tuesday as simply a warning not to attack the United States, albeit one whose tone was more typical of North Korean propagandists than it was of past US presidents. Officials in South Korea and Japan said that while the situation was tense, it had not reached a crisis point.

Secretary of State Rex Tillerson played down any imminent threat from North Korea, saying on Wednesday, "I think Americans should sleep well at night, have no concerns about this particular rhetoric of the last few days". Still, some in the region said that the danger of war had not seemed as clear and present in decades. What was unthinkable just years ago no longer seems so, they said.

"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. He called Trump's language "explosive", and said the threat and counterthreat had resulted in a new stage of confrontation.

Cheng said that he was also puzzled by the timing of 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 programmes. That unanimous vote, which overcame China's historical reluctance to harshly punish its ally, has been widely described as the Trump administration's greatest diplomatic accomplishment so far.

"Usually, the US government is willing to give more time for a resolution, to see how the resolutions bite," Cheng said.

Across the region on Wednesday, analysts reacted with concern and even foreboding about the tone of Trump's comments, as well as about the unimpeded progress that North Korea appears to be making towards becoming a full-fledged nuclear power, able to strike the US or other far-off adversaries.

While Trump's warning that North Korea, if it kept threatening the US, 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 Trump recognised the price that some of the US' staunchest 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, the South Korean 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." Trump's warning followed a report that US 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 US military might for strategic security.

Itsunori Onodera, Japan's new defence minister, said on Wednesday that Japan found it credible that North Korea had succeeded in miniaturising 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 Trump, particularly on Twitter, and they tend to ignore them or treat them as inaccurate reflections of US policy. But analysts saw his "fire and fury" remark as dangerous and unlikely to deter North Korea's leader, Kim Jong Un.

"We are used to painting North Korea as unpredictable, but increasingly it is the US that is introducing strategic unpredictability into a volatile dynamic," Euan Graham, an analyst at the Lowy Institute in Sydney, wrote in an e-mail.

He added that Trump's warning would not have its desired effect because "the North Koreans have an ear for bluster."

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 programme. He said that nations across the region, including his own, needed to start preparing 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 to an inquiry on Wednesday about 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 about the situation, 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 neighbours 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 Wednesday, Pyongyang released a Canadian pastor, Reverend Lim Hyeon Soo, who had been sentenced to a life of hard labour, perhaps in an effort to avoid the potential embarrassment of releasing a prisoner in ill health nearly two months after the death of another prisoner, Otto Warmbier, an American college student.

"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 US president.

In Japan, a senior government official sought to frame Trump's remark as an effort to warn Kim's government that military action remained a possibility, even as the new sanctions begin going into effect.

"He's saying that the United States is putting all options on the table," said the official, Chief Cabinet Secretary Yoshihide Suga. "Our government approves of that stance. It's extremely important that the Japan-US alliance further strengthens its ability to deter and respond." Even so, Trump's language resonated deeply in Japan, which commemorated on Wednesday the 72nd anniversary of an American atomic bomb being dropped on Nagasaki at the end of World War II, three days after using one on Hiroshima.

"The world has seen American fire and fury in Hiroshima and Nagasaki 72 years ago," Kiichi Fujiwara, a professor of international politics at Tokyo University, wrote bitingly on Twitter. He added that for Trump to use such language was "reckless and unwise, even as an act of deterrence."

Tong Zhao, a nuclear policy expert at the Carnegie-Tsinghua Centre for Global Policy in Beijing, said that China still believed that a deal to defuse tensions could be reached, with North Korea agreeing to suspend its nuclear and missile tests in exchange for a halt to joint US and South Korean military exercises. China has raised that possibility repeatedly.

"It's already a fact on the ground that North Korea has a credible nuclear deterrence," he said. "The best we can do at the moment is to deter North Korea's use of nuclear weapons and contain the growth of its nuclear and missile capabilities."