SEOUL • North Korea has warned of a nuclear strike at the heart of the United States if Washington attempts a regime change in Pyongyang, the North's state news agency said on Tuesday.
"Should the US dare to show even the slightest sign of attempt to remove our supreme leadership, we will strike a merciless blow at the heart of the US with our powerful nuclear hammer, honed and hardened over time," the Korean Central News Agency (KCNA) said, quoting a spokesman of the North Korean Foreign Ministry.
The KCNA report, according to South Korea's Yonhap news agency, said remarks by Mr Mike Pompeo, the chief of the US intelligence agency, "have gone over the line, and it has now become clear that the ultimate aim of the Trump administration... is the regime change".
In a forum last week, Mr Pompeo alluded to the possibility of regime change in North Korea by saying that the most important thing the US can do is "separate (nuclear) capacity and someone who might well have (nuclear) intent, and break those two apart".
US officials said on Tuesday they have seen increased North Korean activity at a site in the western city of Kusong that could be preparations for another missile test within days, according to a Reuters report.
A US defence official, speaking on condition of anonymity, told Agence France-Presse that if the test goes ahead, it would "probably" occur today, which is the 64th anniversary of the signing of the Korean Armistice Agreement.
The date is celebrated as Victory Day in the North.
The official said the test would be of either an intermediate range missile or North Korea's intercontinental ballistic missile (ICBM) known as a KN-20 or a Hwasong-14.
Earlier this month, North Korea said it had conducted its first test of an ICBM and mastered the technology needed to deploy a nuclear warhead via the missile.
Pyongyang's state media said the test verified the atmospheric re-entry of the warhead, which experts say may be able to reach the US state of Alaska. But the vice-chairman of the US Joint Chiefs of Staff recently said the July 4 test stopped short of showing North Korea has the ability to strike the US "with any degree of accuracy".
However, a new assessment by the Pentagon's Defence Intelligence Agency has concluded that the regime of North Korean leader Kim Jong Un will be able to produce a "reliable, nuclear-capable ICBM" programme sometime next year, reported the Washington Post.
Already, the aggressive testing regime put in place in recent months has allowed North Korea to validate its basic designs, putting it within a few months of starting industrial production, said the officials familiar with the document.
North Korea has not yet demonstrated an ability to build a miniaturised nuclear warhead that could be carried by one of its missiles.
Another of the few remaining technical hurdles is the challenge of atmospheric "re-entry" - the ability to design a missile that can pass through the upper atmosphere without damage to the warhead.