North Korea said on Friday that it conducted a test of a new underwater nuclear weapon and cruise missile exercise earlier this week under the guidance of leader Kim Jong-un.

According to the North's official Korean Central News Agency(KCNA) on Friday, the Central Military Commission of the Workers’ Party tested the new nuclear underwater attack system from Tuesday to Thursday.

The KCNA said that the "underwater nuclear attack drone" was deployed off the coast of Riwon County of South Hamgyong Province on Tuesday, with the test warhead detonating underwater upon reaching the target off Hongwon Bay on Thursday afternoon.

The drone reportedly traveled for 59 hours and 12 minutes, cruising along an oval and figure-eight course at a depth of 80 to 150 meters underwater.

The KCNA said that the test results verified the reliability and safety of the drone and proved its lethal strike capability.

The state broadcaster also confirmed that the North conducted an exercise on Wednesday with strategic cruise missiles tipped with test payloads simulating nuclear warheads to practice carrying out tactical nuclear attack missions.

The report said that two "Hwasal-1"-type strategic cruise missiles and two "Hwasal-2"-type missiles were launched in South Hamgyong Province and flew 15-hundred and 18-hundred kilometers, respectively, hitting a target set in the East Sea.