SEOUL - North Korea has warned of a nuclear strike at the heart of the United States if Americans attempt a regime change in Pyongyang, the North's state news agency said on Tuesday (July 25).
"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 Yonhap news agency, said remarks by Mr Mike Pompeo, 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 a 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 (July 25) 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 AFP that if the test goes ahead, it would "probably" occur on July 27, which is the 64th anniversary of the signing of the Korean Armistice Agreement.
The date is a public holiday in the nuclear-armed North and celebrated as Victory Day.
The official said the test would be of either an intermediate-range missile or North Korea's 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.
However, 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 United States "with any degree of accuracy".
A new assessment by the Pentagon's Defense Intelligence Agency (DIA) concluded that North Korean leader Kim Jong Un will be able to produce a "reliable, nuclear-capable ICBM" programme sometime in 2018, reported 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, the officials familiar with the document told Washington Post.
North Korea has not yet demonstrated an ability to build a miniaturised nuclear warhead that could be carried by one of its missiles.
Officials there last year displayed a sphere-shaped device the regime described as a miniaturised warhead, but there has been no public confirmation that this milestone has been achieved.
Preparations reportedly have been underway for several months for what would be the country's sixth underground atomic test. The last one, in September, had an estimated yield of 20 to 30 kilotons, more than double the explosive force of any previous test.
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.
A South Korean lawmaker, who attended an intelligence committee briefing after the July 4 test, said North Korea still has not proved it has mastered some of the steps needed to build a reliable ICBM, most notably the re-entry vehicle.