This photo carried on Tuesday shows the North's firing drills involving super-large multiple rocket launchers the previous day. (KCNA)

North Korean leader Kim Jong-un has guided firing drills involving super-large multiple rocket launchers and called for perfecting readiness to collapse the capital of the enemy with the "core striking means," state media said Tuesday.

On the previous day, Kim oversaw the "salvo" drills of artillery units in the country's western region using the 600mm multiple launch rocket system, according to the Korean Central News Agency.

The South Korean military said Monday it detected the firing of multiple short-range ballistic missiles from areas near Pyongyang and they flew about 300 kilometers toward the East Sea. Experts said they might be the KN-25 super-large multiple rocket launcher.

Calling a super-large multiple rocket launcher one of "the core striking means" of its military, Kim said the weapon system has an important role in the country's war preparations, the KCNA said.

"He said that it is necessary to further impress upon the enemies that if an armed conflict and a war break out, they can never avoid disastrous consequences," the report said.

"The destructive offensive means possessed by our army should more thoroughly fulfill their missions to block and suppress the possibility of war with the constant perfect preparedness to collapse the capital of the enemy and the structure of its military forces," Kim was quoted as saying by the KCNA, apparently referring to Seoul.

North Korea also conducted a test simulating the midair detonation of a shell of such a weapon system at a preset altitude above the target, it added.

The North's super-large multiple rocket launch system is classified as a short-range missile that could put the entire South Korean territory within range. Pyongyang has claimed a tactical nuclear warhead could be mounted on such a weapon.

Photos carried by the KCNA showed six missiles being launched simultaneously, but the South Korean military said it assesses that the North staged even more launches.

"(The photos) appear to show the first simultaneous launches, and (we) assess that there were more launches afterward," Lt. Col. Lee Chang-hyun, a spokesperson for the Joint Chiefs of Staff, told a briefing.

Lee said South Korea and the United States are continuing to track the North's weapons development activities, noting that they are assessing the state media report while leaving various possibilities open.

The provocation came as South Korea and the US wrapped up the 11-day annual Freedom Shield exercise Thursday.

It marked North Korea's second ballistic missile launch this year since Jan. 14, when it test-fired a solid-fuel intermediate-range ballistic missile carrying a hypersonic warhead.

North Korea refrained from conducting missile tests during the joint military drills by Seoul and Washington. Instead, its leader Kim Jong-un guided military training involving artillery and tank units as well as paratroopers.

The North's latest missile launch was also timed with US Secretary of State Antony Blinken's visit to Seoul. Blinken arrived in South Korea on Sunday to attend the third Summit of Democracy hosted by South Korea, a US-led multinational gathering formed to boost solidarity and shared values among democratic countries.

In January, the North's leader called for revising the country's constitution to define South Korea as its "primary foe" and codify a commitment to subjugate the South Korean territory in the event of war. (Yonhap)