The US will have “no choice but to totally destroy North Korea” unless Pyongyang backs down on its nuclear ambitions, Donald Trump said on Tuesday, using his debut address to the UN general assembly to issue stark threats to an “evil few” oppressive regimes.

“Rocket man is on a suicide mission for himself and for his regime,” the US president said, referring to North Korean leader Kim Jong Un in terms that brought the casually explosive rhetoric of his Twitter feed to the UN’s formal annual gathering of world leaders and diplomats.

Combining measured explorations of political theory with grander invocations of God and morality, Mr Trump’s speech called on nations of the world to confront and isolate both North Korea and Iran, which he described as rogue regimes that respect neither their own citizens nor the sovereignty of other countries.