North Korea has successfully produced a miniaturized nuclear warhead that can fit inside its missiles, crossing a key threshold on the path to becoming a full-fledged nuclear power, U.S. intelligence officials have concluded in a confidential assessment.
The analysis, completed last month by the Defense Intelligence Agency, comes on the heels of another intelligence assessment that sharply raises the official estimate for the total number of bombs in the communist countryâs atomic arsenal. The United States calculated last month that up to 60 nuclear weapons are now controlled by North Korean leader Kim Jong Un. Some independent experts think the number is much smaller.
The findings are likely to deepen concerns about an evolving North Korean military threat that appears to be advancing far more rapidly than many experts had predicted. U.S. officials concluded last month that Pyongyang is also outpacing expectations in its effort to build an intercontinental ballistic missile capable of striking the American mainland.
President Trump, speaking Tuesday at an event at his golf course in Bedminster, N.J., said North Korea will face a devastating response if its threats continue. âThey will be met with the fire and fury and frankly power, the likes of which this world has never seen before,â he said.
Earlier Tuesday, North Korea described a new round of U.N. sanctions as an attempt âto strangle a nationâ and warned that in response, âphysical action will be taken mercilessly with the mobilization of all its national strength.â
Although more than a decade has passed since North Koreaâs first nuclear detonation, many analysts thought it would be years before the countryâs weapons scientists could design a compact warhead that could be delivered by missile to distant targets. But the new assessment, a summary document dated July 28, concludes that this critical milestone has been reached.
âThe IC [intelligence community] assesses North Korea has produced nuclear weapons for ballistic missile delivery, to include delivery by ICBM-class missiles,â the assessment states, in an excerpt read to The Washington Post. Two U.S. officials familiar with the assessment verified its broad conclusions. It is not known whether the reclusive regime has successfully tested the smaller design, although North Korea officially claimed last year that it had done so.
The DIA and the Office of the Director of National Intelligence declined to comment.
An assessment this week by the Japanese Ministry of Defense also concludes that there is evidence to suggest that North Korea has achieved miniaturization.
Kim is becoming increasingly confident in the reliability of his nuclear arsenal, analysts have concluded, explaining perhaps the dictatorâs willingness to engage in defiant behavior, including missile tests that have drawn criticism even from North Koreaâs closest ally, China. On Saturday, China and Russia joined other members of the U.N. Security Council in approving punishing new economic sanctions, including a ban on exports that supply up to a third of North Koreaâs annual $3Â billion in earnings.
The nuclear progress further raises the stakes for Trump, who has vowed that North Korea will never be allowed to threaten the United States with nuclear weapons. In an interview broadcast Saturday on MSNBCâs âHugh Hewitt Show,â national security adviser H.R. McMaster said the prospect of a North Korea armed with Ânuclear-tipped ICBMs would be âintolerable, from the presidentâs perspective.â
âWe have to provide all options .â.â. and that includes a military option,â he said. But McMaster said the administration would do everything short of war to âpressure Kim Jong Un and those around him, such that they conclude it is in their interest, to denuclearize.â The options said to be under discussion range from new multilateral negotiations to reintroducing U.S. battlefield nuclear weapons to the Korean Peninsula, officials familiar with internal discussions said.
At the same time, the administration has been attempting to push North Korea toward talks, but Pyongyang has shown no interest in dialogue.
Determining the precise makeup of North Koreaâs nuclear arsenal has long been a difficult challenge for intelligence officials because of the regimeâs culture of extreme secrecy and insularity. The countryâs weapons scientists have conducted five nuclear tests since 2006, the latest being a 20- to 30-kiloton detonation on Sept. 9, 2016, that produced a blast estimated to be up to twice that of the bomb dropped on Hiroshima, Japan, in 1945.
But producing a compact nuclear warhead that can fit inside a missile is a technically demanding feat, one that many analysts thought was still beyond North Koreaâs grasp. Last year, state-run media in Pyongyang displayed a spherical device that government spokesmen described as a miniaturized nuclear warhead, but whether it was a real bomb remained unclear. North Korean officials described the September detonation as a successful test of a small warhead designed to fit on a missile, although many experts were skeptical of the claim.
Kim has repeatedly proclaimed his intention to field a fleet of nuclear-tipped ICBMs as a guarantor of his regimeâs survival. His regime took a major step toward that goal last month with the first successful tests of a missile with intercontinental range. Video analysis of the latest test led some analysts to conclude that the missile caught fire and disintegrated as it plunged back toward Earthâs surface, suggesting that North Koreaâs engineers might not be capable yet of building a reentry vehicle that can carry the warhead safely through the upper atmosphere. But U.S. analysts and many independent experts think this hurdle will be overcome by late next year.
âWhat initially looked like a slow-motion Cuban missile crisis is now looking more like the Manhattan Project, just barreling along,â said Robert Litwak, a nonproliferation expert at the Woodrow Wilson International Center for Scholars and the author of âPreventing North Koreaâs Nuclear Breakout,â published by the center this year. âThereâs a sense of urgency behind the program that is new to the Kim Jong Un era.â
Although few discount North Koreaâs progress, some prominent U.S. experts warned against the danger of overestimating the threat. Siegfried Hecker, director emeritus of the Los Alamos National Laboratory and the last known U.S. official to inspect North Koreaâs nuclear facilities, has calculated the size of North Koreaâs arsenal at no more than 20 to 25 bombs. He warned of potential risks that can come from making Kim into a bigger menace than he actually is.
âOverselling is particularly dangerous,â said Hecker, who visited North Korea seven times between 2004 and 2010, and met with key leaders of the countryâs weapons programs. âSome like to depict Kim as being crazy â a madman â and that makes the public believe that the guy is undeterrable. Heâs not crazy and heâs not suicidal. And heâs not even unpredictable.â
âThe real threat,â Hecker said, âis weâre going to stumble into a nuclear war on the Korean Peninsula.â
In the past, U.S. intelligence agencies have occasionally overestimated the North Korean threat. In the early 2000s, the George W. Bush administration assessed that Pyongyang was close to developing an ICBM that could strike the U.S. mainland â a prediction that missed the mark by more than a decade. More recently, however, analysts and policymakers have been surprised repeatedly as North Korea achieved key milestones months or years ahead of schedule, said Jeffrey Lewis, director of the East Asia Nonproliferation Program at the Center for Nonproliferation Studies. There was similar skepticism about Chinaâs capabilities in the early 1960s, said Lewis, who has studied that countryâs pathway to a successful nuclear test in 1964.
âThere is no reason to think that the North Koreans arenât making the same progress after so many successful nuclear explosions,â Lewis said. âThe big question is: Why do we hold the North Koreans to a different standard than we held [Joseph] Stalinâs Soviet Union or Mao Zedongâs China? North Korea is testing underground, so weâre always going to lack a lot of details. But it seems to me a lot of people are insisting on impossible levels of proof because they simply donât want to accept what should be pretty obvious.â
Yuki Oda in Tokyo contributed to this report.