North Korea 'carefully examining' plan to strike Guam with missiles

The threat came hours after President Donald Trump told Pyongyang that any threat to the US would be met with "fire and fury".

A spokesman for the Korean People's Army said the strike plan will be "put into practice in a multi-current and consecutive way any moment" once Kim Jong Un makes a decision.

He added that "enveloping fire" would be used to contain major US military bases on the island territory in the western Pacific Ocean - including the Anderson Air Force Base.

KCNA, Pyongyang's state-run news agency, also carried a statement from a different military official which said North Korea may carry out a pre-emptive operation if the US shows signs of provocation.

Earlier on Tuesday, the Washington Post had reported that North Korea has successfully made a miniaturised nuclear warhead that can fit inside one of its intercontinental ballistic missiles.

The newspaper said that claim was contained in a confidential assessment by America's Defence Intelligence Agency.

An analyst who specialises in North Korea, who asked not to be named, told Sky News that he believes Pyongyang is "a lot more than halfway" to achieving its aims of producing a nuclear weapon capable of exploding above the US mainland.

He added: "It's fair to say it's just a matter of time, in terms of being able to hit the hit the US with a (nuclear) missile."

On Monday, North Korea responded angrily after the UN imposed tough new sanctions on the isolated state following the test firing of intercontinental ballistic missiles.

Pyongyang said the sanctions were caused by a "heinous US plot to isolate and stifle" the country - and its officials also threatened to make America "pay the price for its crime... thousands of times".