North Korea said on Saturday targeting the US mainland with its rockets was inevitable after "Mr Evil President" Donald Trump called Pyongyang's leader "rocket man", further escalating rhetoric over the North's nuclear weapons and missile programs.
North Korean Foreign Minister Ri Yong Ho's remarks to the United Nations General Assembly came hours after US Air Force B-1B Lancer bombers escorted by fighters flew in international airspace over waters east of North Korea in a show of force the Pentagon said showed the range of military options available to Trump.
Ri's speech capped a week of rising tensions between Washington and Pyongyang, with Trump and North Korean leader Kim Jong-Un trading insults.
Trump called Kim a "madman" on Friday, a day after Kim dubbed him a "mentally deranged US dotard."
On Saturday, the mudslinging continued with Ri calling Trump "a mentally deranged person full of megalomania and complacency" who is trying to turn the United Nations into a "gangsters' nest".
Ri said Trump himself was on a "suicide mission" after the US president had said Kim was on such a mission.
"'President Evil' is holding the seat of the US President," Ri said, warning that Pyongyang was ready to defend itself if the United States showed any sign of conducting a "decapitating operation on our headquarters or military attack against our country".
“Now we are finally only a few steps away from the final gate of completion of the state nuclear force,” Ri told the annual gathering of world leaders.
He said sanctions would have no effect on Pyongyang's resolve to develop its nuclear weapons, with the ultimate goal being "balance of power with the US".
