North Korean leader Kim Jong-un, center, observes the test-firing of a tactical ballistic missile in North Korea, in this photo provided by North Korea's official Korean Central News Agency, Sept. 19. Yonhap

North Korea claimed Thursday it has successfully test-fired a new tactical ballistic missile capable of carrying a super-large warhead, a day after South Korea said Pyongyang fired multiple short-range ballistic missiles.

The new missile, named the Hwasongpho-11-Da-4.5, was tipped with a 4.5-ton super-large conventional warhead in the test-firing conducted Wednesday by the North's Missile Administration, according to the official Korean Central News Agency (KCNA).

"Its test-fire was aimed at verifying the accuracy of hit at medium range of 320 kilometers and explosive power of the super-large warhead with a missile loaded with such a warhead," the KCNA said.

The KCNA said the missile administration also conducted a test-fire of a strategic cruise missile whose performance has been highly upgraded for its combat use.

North Korean leader Kim Jong-un guided the test-fires and expressed great satisfaction, it said.

"The military and political situation in the region threatening the present state security environment indicates that the work for bolstering up the military capability for self-defence should be the most important affair of the country," he said.

South Korea's Joint Chiefs of Staff (JCS) said Wednesday it detected multiple short-range ballistic missile launches at about 6:50 a.m. from the North's Kaechon area in South Phyongan Province, north of Pyongyang, and the missiles flew about 400 kilometers.

The launches came after the North claimed to have test-fired the Hwasongpho-11-Da-4.5 with a simulated warhead on July 1 to verify its performance at its maximum and minimum ranges.

It said it would conduct another test at its medium range the same month, but it apparently did not take place at the time.

This picture shows a test-firing of a tactical ballistic missile in North Korea, in this photo provided by the North's official Korean Central News Agency, Sept. 19. Yonhap

The JCS said Thursday it had detected both the ballistic and cruise missile launches the previous day, and the missiles disclosed by the North's state media landed in a mountainous area in North Korea's northeastern province of North Hamgyong.

Photos released by the KCNA showed a missile hitting an apparent inland target, marking the first public disclosure of its kind by the North, which has usually fired missiles into waters off its eastern and western coasts.

South Korea's military has immediately notified the media of North Korean ballistic missile launches, which are in violation of U.N. Security Council resolutions, but has disclosed cruise missile launches depending on the threat they pose to the South.

When asked about the North's report of the missile's range of 320 km compared with its assessment of about 400 km, the JCS stood by its analysis, clarifying it is based on the trajectory of the missile that covered the longer distance.

"North Korea revealed that it flew some 320 km, but we believe there is a possibility of deception," Col. Lee Sung-jun, spokesperson of the JCS, told a regular briefing.

A super-large warhead is among a list of high-tech weapons that Kim had vowed to develop at a party congress in 2021, including a spy military satellite and solid-fuel intercontinental ballistic missiles.

In June, the North claimed it had successfully conducted a multiple warhead missile test, but South Korea's military at the time dismissed it as "deception," saying the launch ended in failure as the missile exploded in midair. (Yonhap)