North Korea said Saturday it carried out another test of an underwater nuclear-capable attack drone this week, proving the weapon system's reliability and "deadly" striking capability.

The North tested the "Haeil-2" underwater strategic weapon system from April 4-7, according to the Korean Central News Agency (KCNA).

The drone cruised along an "oval and eight-shaped" course simulating a distance of 1,000 kilometers in the East Sea for 71 hours and six minutes and set off a test warhead underwater, it said.

The test came about two weeks after the North first unveiled the test of its underwater attack drone Haeil which it claims is capable of spawning a "radioactive tsunami" and stealthily attacking enemies.

Source: Yonhap News Agency