North Korea's Foreign Minister Ri Yong Ho told the United Nations General Assembly that targeting the US mainland with rockets was inevitable after "Mr Evil President" Trump called Pyongyang's leader a "rocket man" on a suicide mission.

The leaders have traded increasingly threatening and personal insults recently as Pyongyang races towards its goal of developing a nuclear-tipped missile capable of reaching the United States.

Analysts say the escalation in rhetoric is increasing the risk of a miscalculation by one side or the other that could have massive repercussions.