WASHINGTON - President Donald Trump issued an apocalyptic warning to North Korea on Tuesday, saying it faces "fire and fury" over its missile program, hours after US media reported Pyongyang has successfully miniaturized a nuclear warhead.
"North Korea best not make any more threats to the United States," said Trump, who was speaking at his golf club in New Jersey. "They will be met with fire and fury like the world has never seen."
Hours later, North Korea said it was considering strikes near US strategic military installations in Guam with its intermediate range ballistic missiles, state news agency KCNA reported.
Pyongyang is "carefully examining the operational plan for making an enveloping fire at the areas around Guam with medium-to-long-range strategic ballistic rocket Hwasong-12."
The plan could be put into motion "any moment" once North Korean leader Kim Jong-Un makes a decision, the KCNA report said.
It was not immediately clear whether the threat was in response to Trump's statements.
The Washington Post had quoted a Defense Intelligence Agency analysis as saying officials think North Korea now has "nuclear weapons for ballistic missile delivery" -- including in its intercontinental ballistic missiles -- making it a potent threat against neighbours and possibly the United States.
The Pentagon did not comment on the story, but the Post said two US officials familiar with the analysis had verified the assessment's broad conclusions, and CNN said it had confirmed the report.
The development suggests North Korea is further along the path to having a deployable nuclear missile than had previously been acknowledged.
Experts had until last month said it would take another two or three years for North Korea to develop a nuclear-tipped ICBM.
That calculus suddenly changed after Pyongyang in July tested two ICBMs -- the first time Kim had demonstrated such a capability.
The first of these trials, which Kim described as a gift to "American bastards," showed the rocket had the potential range to hit Alaska.
The second rocket tested flew even longer, with some experts even suggesting New York could be vulnerable.
Trump said Kim "has been very threatening beyond a normal state."
"As I said, they will be met with the fire and fury and, frankly, power," he told reporters.
The remarks mark a sharp rise in rhetoric from the United States. Administration comments have generally focused on finding non-military solutions.
Congressman Eliot Engel, who is the Democratic senior member of the House Committee on Foreign Affairs, said Trump's remarks sounded crazy and chastised him for drawing an "absurd" red line that Kim would inevitably cross.
"Make no mistake: North Korea is a real threat, but the president's unhinged reaction suggests he might consider using American nuclear weapons in response to a nasty comment from a North Korean despot," Engel said in a statement.
Pentagon spokesman Lieutenant Colonel Chris Logan said the United States seeks a peaceful de-nuclearization of the Korean Peninsula, but he indicated military action is never off the table.
"We remain prepared to defend ourselves and our allies and to use the full range of capabilities at our disposal against the growing threat from North Korea," Logan said.
Deputy Secretary of State John Sullivan said the department continues to work to make sure China and other countries enforce tough new sanctions.
"We're not going to come to the table until the North Koreans have committed to" stopping their missile tests, Sullivan said.
The Post also reported that another intelligence assessment estimated that North Korea now has up to 60 nuclear weapons, more than previously thought.
Despite the advance, North Korea still must overcome technical hurdles before it can claim to have perfected its nuclear weapons technology.
After Kim's second ICBM test, experts said it appeared the "re-entry vehicle" that would carry a warhead back into Earth's atmosphere from space had failed.
Without proper protection during a re-entry stage, a missile's warhead would burn up.
"North Korea likely made some of the key measurements required to define those extreme conditions during the two July tests, but I can't imagine it has learned enough to confidently make a warhead that is small and light enough and sufficiently robust to survive," Stanford University expert Siegfried Hecker said in an interview with the Bulletin of the Atomic Scientists.
The former Los Alamos National Laboratory director said he did not think North Korea yet has sufficient missile or nuclear test experience "to field a nuclear warhead that is sufficiently small, light and robust to survive an ICBM delivery."
News that Kim appears to have produced a small nuclear warhead comes as international tensions flare around Pyongyang's program.
"Especially since last year, when it pushed ahead with two nuclear tests and launched more than 20 ballistic missiles, it has posed a new level of threat," Japan's defence ministry said in an annual report.
North Korea has vowed that tough new UN sanctions agreed over the weekend would not stop it from developing its nuclear arsenal, rejecting talks and angrily threatening retaliation against the United States.