“Rocket Man,” meet “Frightened Dog.”

The war of words escalated Thursday between President Trump and Kim Jong Un, with the North Korean president calling his US counterpart “mentally deranged” and mocking him as a mere “frightened dog.”

Speaking in a rare personal address on North Korean television, Kim also called him a “rogue” and a “gangster.”

Kim concluded his address with this promise: “I will surely and definitely tame the mentally deranged US dotard with fire.”

The name-calling is North Korea’s response to Trump’s first formal United Nations General Assembly address on Tuesday, during which he derided Kim as a “Rocket Man on a suicide mission for himself and his regime.”

Trump also promised that if North Korea threatens the US or its allies, he would “totally destroy” the rogue regime.

Trump’s remarks are being taken as a “war declaration,” Kim thundered, adding that North Korea “will consider with seriousness exercising of a corresponding, highest level of hard-line countermeasures in history,” Kim said, in a statement translated by Conflict News.

“Far from making remarks of any persuasive power that can be viewed to be helpful to defusing tension, [Trump] made unprecedented rude nonsense one has never heard from any of his predecessors,” Kim said.

“A frightened dog barks louder,” Kim taunted.

“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.

“The mentally deranged behavior of the US president openly 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 faculty think about discretion and composure,” Kim said, according to Conflict News.

Trump is also “unfit to hold the prerogative of supreme command of a country, and he is surely a rogue and a gangster fond of playing with fire, rather than a politician,” Kim wrote.

Trump’s remarks Tuesday “have convinced me, rather than frightening or stopping me, that the path I chose is correct and that it is the one I have to follow to the last,” Kim wrote.

Trump will “pay dearly for his speech,” he wrote.