North Korea claimed Friday that it tested two surface-to-surface tactical guided missiles and two long-range cruise missiles this week with "successful" results.

Pyongyang carried out the launches to 'update' the cruise missile system and to 'confirm' "the power of conventional warhead for surface-to-surface tactical guided missile," according to the state Korean Central News Agency.

On Tuesday, "two long-range cruise missiles flew for 9 137 s along the flight trajectory over the East Sea of Korea (Sea of Japan) to hit the target island 1 800 km away," KNCA said, adding the performance would boost "war deterrence."

On Thursday, the two surface-to-surface missiles "precisely hit the target island, proving that the explosive power of the conventional warhead complied with the design requirements," according to the KCNA.