North Korea on Saturday warned Japanese Prime Minister Shinzo Abe that he could soon see a "real ballistic missile" while excoriating him as the "most stupid man ever known in history".
The colourful condemnation comes two days after the isolated state tested what it called a "super-large multiple launch rocket system", with South Korea reporting that two projectiles came down in the Sea of Japan, also known as the East Sea.
In the wake of the launch, which was supervised by North Korean leader Kim Jong Un, Abe termed the fired weapons "ballistic missiles" that violated UN resolutions.
"It can be said that Abe is the only one idiot in the world and the most stupid man ever known in history as he fails to distinguish a missile from multiple launch rocket system while seeing the photo-accompanied report," a foreign ministry official said in a statement carried by state news agency KCNA.
"Abe may see what a real ballistic missile is in the not distant future and under his nose... Abe is none other than a perfect imbecile," it added.
It was best for the North to avoid dealing with Abe, the official went on, adding that doing so with a "political dwarf" would bring "disgrace".
The Saturday criticism of the Japanese leader is the second of its kind by Pyongyang this month.
The North had slammed him as an "idiot and villain" and warned he will never set foot in Pyongyang after he condemned the North's weapons test days earlier.
Pyongyang is under multiple sets of international sanctions over its nuclear weapon and ballistic missile programmes, which it says it needs to defend against a possible US invasion.
Nuclear negotiations between the US and the North have been at a standstill since the Hanoi summit between President Donald Trump and leader Kim Jong Un broke up in February, and Pyongyang has since demanded Washington change its approach by the end of the year.
North Korea has issued a series of increasingly assertive comments in recent weeks as time runs down on its end-of-year deadline.
Trump hinted at the prospect of a fourth meeting with Kim in a tweet earlier this month, only to be rebuffed by the North, which said it had no interest in summits "that bring nothing to us".