North Korea has conducted a new underwater nuclear strategic weapon test and cruise missile exercise guided by leader Kim Jong-un earlier this week, Pyongyang's state media said Friday.

The North's Central Military Commission of the Workers' Party commanded the drills from March 21 to 23 "in order to alert the enemy to an actual nuclear crisis and verify the reliability of the nuclear force for self-defence," the official Korean Central News Agency (KCNA) said.

The "underwater nuclear attack drone" was deployed off the coast of Riwon County of South Hamgyong Province on Tuesday and reached the target point in the waters off Hongwon Bay set as a mock enemy port with its test warhead detonating underwater on Thursday afternoon, according to the KCNA.

The drone cruised "along an oval and pattern-8 course at an underwater depth of 80 to 150 meters in the East Sea of Korea for 59 hours and 12 minutes," it added.

On Wednesday, the North launched strategic cruise missiles "tipped with a test warhead simulating a nuclear warhead."

The KCNA said two "Hwasal-1"-type strategic cruise missiles and two "Hwasal-2"-type strategic cruise missiles, launched in South Hamgyong Province, accurately hit the target set in the East Sea.

It then slammed the U.S. and the "South Korean puppet regime of traitors" for staging "intentional, persistent and provocative war drills," saying that the exercises have "driven the military and political situation of the Korean peninsula to an irreversibly dangerous point."

Source: Yonhap News Agency