Trump called the leader a "madman" and said he "would be tested like never before," in an early-morning tweet.
“I will surely and definitely tame the mentally deranged U.S. dotard with fire,” Kim said on Thursday, according to The Associated Press. Dotard is a word used to describe an elderly person in a state of senile decay, according to the Merriam-Webster dictionary.
The latest war of words between the two leaders began when the United Nations Security Council unanimously passed new sanctions on North Korea earlier this week in response to the growing nuclear threat posed by the country.
In his address to the U.N. on Tuesday, President Trump threatened to “totally destroy” North Korea.
“The United States has great strength and patience, but if it is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea,” the president said in his address. “Rocket Man is on a suicide mission for himself.”
Responding to the speech, Kim released a statement saying that Trump will “pay dearly” for his address to the U.N. and that North Korea is considering the strongest possible response to what he calls Trump’s provocation.
"I'd like to advise Trump to exercise prudence in selecting words and to be considerate of whom he speaks to when making a speech in front of the world," Kim said, according to The Associated Press.
North Korea Foreign Minister Ri Yong-ho, who is in New York for the UN General Assembly, said Thursday evening that North Korea could detonate an hydrogen bomb over the Pacific Ocean, but also told reporters, "We have no idea about what actions could be taken as it will be ordered by leader Kim Jong Un."