N.Korea says rockets to U.S. 'inevitable' after Trump dubs Kim 'rocket man'

North Korea said on Saturday (September 23) that firing its rockets at the U.S. mainland was "inevitable" after U.S. President Donald Trump called Pyongyang's leader "rocket man", in a further escalation of rhetoric between the two leaders.

North Korean Foreign Minister Ri Yong Ho's remarks before the United Nations General Assembly came hours after U.S. Air Force B-1B Lancer bombers escorted by fighter jets flew in international airspace over waters east of North Korea, in a show of force the Pentagon said demonstrated the range of military options available to Trump.

"Due to his [Trump's] lacking of basic common knowledge and proper sentiment, he tried to insult the supreme dignity of my country by referring it to a rocket. By doing so, however, he committed an irreversible mistake of making our rockets' visit to the entire U.S. mainland inevitable all the more. None other than Trump himself is on a suicide mission. In case innocent lives of the U.S. are lost because of this suicide attack. Trump will be held totally responsible," Ri told the annual gathering of world leaders.

Trump announced new U.S. sanctions on Thursday that he said allow targeting of companies and institutions that finance and facilitate trade with North Korea. Earlier this month the U.N. Security Council unanimously adopted its ninth round of sanctions on Pyongyang to counter its nuclear and ballistic missiles programs.

Ri warned Pyongyang was ready to defend itself if the U.S. showed any sign of conducting a "decapitating operation on our headquarters or military attack against our country".

North Korea has launched dozens of missiles this year, several flying over Japan, as it accelerates its program aimed at enabling it to target the United States with a nuclear-tipped missile.