Kim Jong-un warns Donald Trump he will 'pay dearly' for 'deranged' threats

Kim Jong-un has hit back at Donald Trump, after the US President called him "rocket man" at the United Nations General Assembly on Thursday.

Mr Trump said the North Korean leader was "on a suicide mission for himself and for his regime", and that North Korea would be "totally destroyed" if it attacked the US or its allies. 

In a statement released by North Korea's news agency KCNA on Friday (NZ time), Mr Kim warned the US leader he would "pay dearly" for his "deranged" threats, and that North Korea would consider countermeasures. 

"The mentally deranged behaviour of the US President opening expressing on the UN arena the unethical will to 'totally destroy' a sovereign state, beyond the boundary of threats of regime change or overturn of social system, makes even those with normal thinking think about discretion and composure," said Mr Kim in the statement. 

"His remarks which describe the US option through straightforward expression of his will have convinced me, rather than frightening or stopping me, that the path I chose is correct."

Mr Kim also referred to Mr Trump as a "gangster fond of playing with fire, rather than a politician", and insisted the US President was simply responding with threats out of fear.

"A frightened dog barks louder," he said.