North Korea should stop any actions that "would lead to the end of its regime and the destruction of its people", the US defence secretary has warned.

James Mattis's comments come after a threat by Pyongyang that it was "carefully examining" a plan to strike the US Pacific territory of Guam, where the US runs a naval base and Coast Guard station.

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

Image: North Korea threatened the tiny Pacific island of Guam, home to US bases

The threat was prompted by a statement from President Trump, in which he said that any threat to the US would be met with "fire and fury".

Mr Mattis said in a statement that the US and its allies would win any arms race or conflict with North Korea.


"The DPRK (Democratic People's Republic of Korea) must choose to stop isolating itself and stand down its pursuit of nuclear weapons," he said.

President warns Kim: Stop threatening the US

"The DPRK should cease any consideration of actions that would lead to the end of its regime and the destruction of its people."

US defence officials now believe North Korea has successfully made a miniaturised nuclear warhead that can fit inside one of its intercontinental ballistic missiles, according to a Washington Post report.

Recent tests of the missiles have drawn worldwide condemnation and led to fresh UN sanctions against North Korea.

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State Department spokeswoman Heather Nauert said during a Wednesday briefing: "We've talked about our pressure campaign that's backed by many other nations... that campaign is working, it is ratcheting up the pressure.

Image: North Korea launched another missile on 28 July

"There are lots of ways, we believe, to get through to Kim Jong Un and his regime - our issue is not with the people of the DPRK but with the regime itself."

US secretary of state Rex Tillerson said President Trump had delivered such a stark message because the North Korean leader "doesn't seem to understand diplomatic language".

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He said Mr Trump wanted to "avoid any miscalculation" by Pyongyang and make clear that the US has the "unquestionable ability to defend itself".

Ms Nauert faced intense questioning during the press briefing surrounding the events of the last few days, particularly on the tough language being used by the US.

22 times Trump took on North Korea

"It is a big deal what is going on - it is a concern to the world, not just the United States," she said.

"The international community is in agreement with the United States and many of our partners and allies, on putting additional pressure on North Korea."