President Donald Trump gave North Korea an apocalyptic warning on Tuesday, saying it faced "fire and fury" over its weapons programs, as Pyongyang said it was considering a missile strike near the US territory of Guam.

Trump's comments marked a sharp intensification of Washington's rhetoric over the North's nuclear and missile programmes -- and his bellicose tone triggered expressions of concern from China as well as from US politicians and foreign allies.

The language the president used echoed that adopted by Pyongyang in its habitual promises to turn enemies like South Korea into a "sea of flames".

"North Korea best not make any more threats to the United States," said Trump, speaking from his golf club in New Jersey. "They will be met with fire and fury like the world has never seen."

North Korea raised the stakes just hours later, saying it was considering missile strikes near US strategic military installations on the Pacific US territory of Guam.

Once finalised, the plan could be put into action at "any moment" once leader Kim Jong-Un made a decision, the official Korean Central News Agency quoted a military statement as saying.

The remote island of Guam -- a 210-square-mile dot in the Pacific – is a key US military outpost and home to some 6,000 US troops spread across facilities including the sprawling Anderson Air Force Base, as well as Naval Base Guam.

Guam-based US B1- bombers overflew the Korean peninsula on Tuesday, which KCNA said "proves that the US imperialists are nuclear war maniacs".

Earlier, the Washington Post quoted a Defense Intelligence Agency analysis as saying officials think North Korea now has "nuclear weapons for ballistic missile delivery" -- including by its intercontinental ballistic missiles (ICBMs) -- 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.

- 'Unhinged reaction' -

Experts have long differed over the North's exact capabilities, and a similar DIA assessment four years ago was dismissed by other intelligence organisations.

But all agree it has made rapid progress under Kim Jong-Un.

Last month Pyongyang carried out its first two successful ICBM launches, the first -- described by Kim as a gift to "American bastards" -- showing it could reach Alaska, and the second extending its range even further, with some experts 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.

US officials have repeatedly said this year that military action against the North was an "option on the table".

Trump's tone was markedly different to Secretary of State Rex Tillerson's assurances last week that Washington was not seeking regime change in Pyongyang, and his comments drew a mixed response at home and abroad.

The North's main ally China warned against "words and actions" that would stoke tensions, while Germany said it was watching the "increasing rhetorical escalation" with concern.

But France praised Trump's "determination" in standing up to Pyongyang.

Republican US Senator John McCain said Trump should tread carefully when speaking about the North, telling a US radio station: "All it's going to do is bring us closer to some kind of serious confrontation."

On Guam, Governor Eddie Calvo downplayed Pyongyang's statement, saying that "currently there is no threat" and the territory was "prepared for any eventuality." 

- Technical hurdles -

The North's current ability to launch an accurate nuclear strike remains open to question, with analysts suggesting it has yet to overcome some major technical hurdles.

After Kim's second ICBM test, some experts said it appeared the "re-entry vehicle" that would carry a warhead back into Earth's atmosphere from space had failed in the intense heat.

Former Los Alamos National Laboratory director Siegfried Hecker told the Bulletin of the Atomic Scientists he did not think North Korea yet had sufficient missile or nuclear test experience "to field a nuclear warhead that is sufficiently small, light and robust to survive an ICBM delivery".

North Korea has vowed that tough new UN sanctions agreed last weekend would not stop it from developing its nuclear arsenal, and that it would never negotiate it away.

In a separate development Wednesday, Pyongyang announced the release on medial grounds of a Canadian pastor jailed nearly 2-1/2 years ago for meddling in state affairs

Source: AFP