Concern of an armed clash over North Korea’s nuclear weapons program reached new heights Tuesday as an angry President Trump warned that Pyongyang could soon face “fire and fury like the world has never seen” amid reports that the North has managed to build a nuclear bomb small enough to fit inside an intercontinental ballistic missile.
Mr. Trump’s outburst, which brought both criticism and praise from Capitol Hill, followed the revelation that Japanese analysts and at least one U.S. intelligence agency had concluded that the regime of North Korean leader Kim Jong-un was proceeding much faster than previously thought in obtaining a nuclear weapon capable of hitting much of the U.S. mainland as well as key American allies across East Asia.
U.S. intelligence officials sought to calm nerves about the situation by asserting that a Washington Post news report about a confidential Defense Intelligence Agency analysis on North Korea’s progress toward miniaturization had not revealed anything that American authorities haven’t been aware of for months.
“This is just the latest drip of alleged classified information about the North’s program,” said one intelligence official, who spoke on the condition of anonymity with The Washington Times and refused to confirm or deny the accuracy of the DIA analysis.
While the DIA and the Office of the Director of National Intelligence declined to comment on The Post’s report, a separate assessment released Tuesday by Japan’s Defense Ministry concluded it was “possible that North Korea has achieved the miniaturization of nuclear weapons.”
Mr. Trump’s intense rhetoric mirrored in a way the often apocalyptic, belligerent tone North Korea has long used to threaten its neighbors, heightening fears that the escalating rhetorical war could lead one side or the other to miscalculate.
While not directly responding to Mr. Trump, Pyongyang voiced defiance again Tuesday to tightening economic sanctions and a series of recent U.S. military moves, warning its citizens in a statement that “packs of wolves are coming in attack to strangle a nation.” The North also said it was “carefully examining” a plan to attack Guam, the U.S. territory in the western Pacific that includes a major American air base.
While the Trump administration has just successfully pushed for tougher United Nations sanctions on the isolated North Korean economy, Mr. Trump was clearly frustrated when he spoke to reporters while on a summer working vacation at his private golf course in New Jersey.
“North Korea best not make any more threats to the United States,” the president said, speaking before a briefing on the nation’s opioid abuse crisis. “They will be met with fire, fury and, frankly, power, the likes of which this world has never seen before.”
Several prominent Democrats — and at least one key Republican — criticized the president for inflaming a delicate situation with his comments.
“That kind of rhetoric, I’m not sure how it helps,” Senate Armed Service Committee Chairman John McCain told an Arizona radio station.
“I take exception to the president’s words because you’ve got to be sure you can do what you say you’re going to do,” the Arizona Republican said.
Sen. Dianne Feinstein, the ranking Democrat on the Senate Select Committee on Intelligence, said “there is no question that North Korea is seeking to add a nuclear warhead to an ICBM capable of reaching the United States.”
Although the threat has clearly grown more grave, said the California Democrat, the U.S. approach should be to diplomatically “engage North Korea in a high-level dialogue without any preconditions.”
“What this tells me is that our policy of isolating North Korea has not worked,” said Ms. Feinstein, who asserted that “President Trump is not helping the situation with his bombastic comments.”
But some said Mr. Trump, who recently declared the “era of strategic patience with North Korea is over,” provided a bracing clarity in the face of continued provocations and slights from Pyongyang. North Korea’s neighbors, including critical ally China, are now on notice of the new U.S. administration’s determination to act.
If the news reports are true, the claim about North Korean nuclear weapon miniaturization “undoubtedly represents the greatest crisis since the Cuban Missile Crisis,” Rep. Darrell E. Issa, California Republican, told CNN.
The developments came to light just days after the U.N. Security Council slapped its toughest sanctions yet on North Korea as punishment for a series of recent tests of a ballistic missile that could be used to deliver a nuclear weapon.
Despite the increasing tempo of such tests in recent years, U.S. analysts are uncertain about the North Korea’s ability to couple such a missile with a nuclear device.
A successful miniaturization of a nuclear bomb would signal a major advance by Pyongyang toward the development of nuclear-armed intercontinental ballistic missiles capable of reaching the U.S. mainland.
The Post article, citing unidentified U.S. intelligence officials, claimed the DIA’s confidential analysis of the situation was completed last month and that the agency analysts also calculated that North Korea has up to 60 nuclear weapons, more than double the number in independent assessments.
Alarm in Washington over Pyongyang’s pursuit of a nuclear capability intensified after the North conducted two tests of intercontinental ballistic missiles last month, both reaching farther than any previous North Korean missile had been capable of flying.
It was not clear if Mr. Trump’s blunt comments signal a major diplomatic or military shift on North Korea. So far, the White House has embraced the long-elusive approach of recruiting China to contain Pyongyang and curb its weapons programs. Secretary of State Rex W. Tillerson, on a just-concluded trip to Southeast Asia, took a noticeably more restrained tone, saying the U.S. wasn’t seeking regime change in Pyongyang and was open to talks if North Korea halted its nuclear programs and ballistic missile tests.
While the administration has praised the U.N. sanctions and promised to push hard on regional powers including Russia and China, senior White House officials have also spent recent days stressing what a potentially game-changing development it would be if Pyongyang was found to have operable nuclear ICBMs.
National Security Adviser H.R. McMaster said in an interview with MSNBC on Saturday that the president has deemed it intolerable for North Korea to have nuclear-armed ICBMs that could threaten the U.S. mainland and that the administration had to provide all options to prevent such a development, including a military option.
Director of National Intelligence Daniel Coats told Congress in May that North Korea’s Mr. Kim is “intent on proving he has the capability to strike the U.S. mainland with nuclear weapons” and alluded to U.S. intelligence that Pyongyang had already achieved miniaturization of a warhead.
Specifically, Mr. Coats, whose remarks were part of the intelligence community’s annual Worldwide Threat Assessment, said Mr. Kim had been “photographed beside a nuclear warhead design and missile airframes to show that North Korea has warheads small enough to fit on a missile.”
The anti-war group Peace Action also criticized Mr. Trump’s comments. “Yet again, the president is counting on dangerous threats of military force to convince North Korea to back away from its goal of fielding a nuclear arsenal capable of striking the United States,” the group’s executive director, Jon Rainwater, said in a statement.
• Carlo Muñoz contributed to this article, which is based in part on wire service reports.