The announcement comes about three months after North Korea said it would equip its military with a "new" 240mm multiple rocket launcher (MRL) known to be capable of striking Seoul.

The isolated, nuclear-armed country has recently bolstered military ties with Moscow, and analysts have said the North could be testing and ramping up production of artillery and cruise missiles before sending them to Russia for use in Ukraine.

The United States and Seoul have accused North Korea of supplying ammunition and missiles for Russia's war effort, a claim Pyongyang has called "absurd".

The multiple rocket launcher, "technically updated in its maneuverability and concentrated firing capability, was proved to be advantageous in all indices," Pyongyang's official Korean Central News Agency said Wednesday.

Updates included "newly applied guiding system, controllability and destructive power," it said.

At the test-firing, Kim also "set forth an important policy to be pursued in producing new artillery pieces and equipping army units with them," it added without providing details.

The Wednesday report came just two days after the North unveiled a "suicide drone" designed to be deliberately crashed into enemy targets, effectively acting as guided missiles.

The North said in February it had developed a new control system for a multiple rocket launcher that would lead to a "qualitative change" in its defence capabilities.

In May, it said the updated launcher would be "deployed to units of the Korean People's Army as replacement equipment from 2024 to 2026".

- Seeking a firepower advantage -

North Korea's older MRL was produced around the 1980s, and while capable of striking South Korean frontline units or the Seoul metropolitan area, they had "limitations in explosive power and precision", said Hong Min, a senior analyst at the Korea Institute for National Unification.

It was also difficult to "secure an advantage in firepower compared to US-South Korean forces" with the older weapons, Hong said.

To counter Seoul and Washington -- which have overwhelming air superiority -- Pyongyang is pursuing "enlargement, range extension, and guidance capabilities" of rocket launchers intended to "rapidly destroy" South Korean airfields, he told AFP.

Inter-Korean relations are at one of their lowest points in years, with Pyongyang declaring the South its "principal enemy".

It has shuttered agencies dedicated to reunification and threatened war over "even 0.001 mm" of territorial infringement.

The test-firing came as South Korea and the United States have been carrying out their annual Ulchi Freedom Shield joint military drills, which run until Thursday, with new exercises aimed at containing the nuclear-armed North.

North Korea -- which attacked its neighbour in 1950, triggering the Korean War -- has always been infuriated by joint US-South Korean military exercises, decrying them as rehearsals for invasion.

"While maintaining a solid combined defense posture, our military will conduct the UFS exercise and combined field training drills normally as planned," Seoul's Joint Chiefs of Staff official said in a statement.

They added that the military was "closely monitoring signs of North Korean provocations and military activities".

"If North Korea engages in provocation, we will respond overwhelmingly and decisively in accordance with the principle of 'immediate, strong, and final' action," it added.