In an unprecedented personal statement, Mr Kim said Mr Trump would “pay dearly” for a UN speech where he threatened to “totally destroy” the North if the US was forced to defend itself.
Mr Trump responded that the “madman… will be tested like never before”.The two countries have engaged in ever more heated rhetoric in recent months.
China responded to the war of words, warning that the situation was “complicated and sensitive”.
“All relevant parties should exercise restraint instead of provoking each other,” said Foreign Minister spokesman Lu Kang.
Russia also urged restraint. Kremlin spokesman Dmitry Peskov said Moscow was “deeply concerned by an escalation of tensions”.
What does Kim’s ‘dotard’ insult mean?What missiles and nuclear weapons does North Korea have?
North Korea has been testing missiles at an unprecedented rate, and conducted its sixth nuclear test despite international condemnation.
North Korean Foreign Minister Ri Yong-ho, who had earlier compared Mr Trump’s speech to “the sound of a barking dog” has warned that Pyongyang could test a hydrogen bomb in the Pacific Ocean in response to the US president’s threat.
“It could be the most powerful detonation of an H-bomb in the Pacific,” Mr Ri said, quoted by South Korea’s Yonhap news agency.However, he added: “We have no idea about what actions could be taken as it will be ordered by leader Kim Jong-un.”