North Korea has conducted another test of a nuclear-capable underwater attack drone, state media KCNA reported on Saturday. The drone, 'Haeil-2', was tested from April 4 to April 7. The drone reportedly cruised 1,000 km and successfully hit a simulated target. Last month, Pyongyang claimed it'd tested an underwater nuclear attack drone 'Haeil-1' that could unleash a "radioactive tsunami".