Donald Trump stepped up his Twitter onslaught on the leadership of North Korea, this time turning his fire on the country's foreign minister, Ri Yong Ho.

He said he - and Kim Jong-un - would not be 'around much longer' - if Ri echoed the sentiments of "Little Rocket Man", the US president's latest nickname for the North Korean dictator.

Over the past week, Mr Trump has threatened to totally destroy North Korea, while Ri Yong Ho suggested Pyongyang was ready to test an H-bomb over the Pacific.

In turn, the North Korean foreign minister told the UN that aiming rockets at the US was inevitable after the US president's previous volley of insults.

Last week Sergey Lavrov, the Russian foreign minister, described the escalating war of words between the two leaders as a kindergarten fight.

In Pyongyang, North Korea staged a massive rally condemning the US and extolling the virtues of Kin Jong-un.

Speakers lined up to condemn Washington and marchers carried signs with an array of slogans including as "decisive revenge" and "death to the American imperialists."