North Korea claims to be "only a few steps away from the final gate of completion of the state's nuclear force"
Donald Trump has made fresh threats against the North Korean regime after it branded him a "mentally deranged megalomaniac."
The US President warned Pyongyang's foreign minister that if he if "he echoes thoughts" of the country's leader Kim Jong Un they both "won't be around much longer."
He was responding after Ri Yong Ho told the United Nations General Assembly on Saturday that targeting the US mainland with its rockets was inevitable after "Mr Evil President" made an "irreversible mistake" by calling Mr Kim "rocket man."
Describing Mr Trump as a "mentally deranged person full of megalomania," Mr Ri went on to tell the annual gathering of world leaders that the country was now "only a few steps away from the final gate of completion of the state's nuclear force."
Hitting back on Twitter, Mr Trump wrote: "Just heard Foreign Minister of North Korea speak at UN If he echoes thoughts of Little Rocket Man, they won't be around much longer."
Just heard Foreign Minister of North Korea speak at U.N. If he echoes thoughts of Little Rocket Man, they won't be around much longer!— Donald J. Trump (@realDonaldTrump) September 24, 2017
Shortly before Mr Ri was scheduled to speak at the assembly, the Pentagon announced a fleet of US bombers and fighter jets had flown off North Korea's coast, in what it called a "clear message" to Pyongyang.
Pentagon spokeswoman Dana White said it underlined the range of military options available to the US.
On Thursday, Mr Trump announced new sanctions to any companies and institutions that finance and facilitate trade with North Korea.
Mr Ri did not comment on the military show of force, but added there is no "chance that North Korea would be shaken an inch or change its stance due to the harsher sanctions by the hostile forces."
He added Pyongyang does not have "any intentions to use or threaten to use nuclear weapons against countries that do not join the US in military actions."
On Friday, the US President publicly branded Mr Kim a "rocket man" and said American "really had no choice" but to confront the authoritarian regime.
Mr Kim branded the speech the "most ferocious declaration of war in history" and said he would consider the "highest level of hard-line countermeasure" in response.
Tensions between Pyongyang and Washington have increased in the past few weeks and intensified when the North conducted its sixth and largest nuclear test on 3 September. It has also threatened to test a hydrogen bomb over the Pacific.
Earlier this month, the UN Security Council unanimously adopted its ninth round of sanctions on Pyongyang in response to the nuclear test.