SEOUL: North Korea claimed to have tested a nuclear-capable underwater drone designed to generate a gigantic “radioactive tsunami” that would destroy naval strike groups and ports.

Analysts were sceptical that the device presents a major new threat, but the test underlines the North’s commitment to raising nuclear threats.

The test this week came as the United States reportedly planned to deploy aircraft carrier strike groups and other advanced assets to waters off the Korean Peninsula.

Military tensions are at a high point as the pace of both North Korean weapons tests and US-South Korea joint military exercises has accelerated in the past year in a cycle of tit-for-tat responses.

Pyongyang’s official Korean Central News Agency said the new weapon, which can be deployed from the coast or towed by surface ships, is built to “stealthily infiltrate into operational waters and make a super-scale radioactive tsunami through an underwater explosion to destroy naval strike groups and major operational ports of the enemy”.

The report came hours before South Korean President Yoon Suk-yeol pledged to make North Korea pay for its “reckless provocations” as he attended a remembrance service honouring 55 South Korean troops killed during major clashes with the North near their western sea border in past years.

The testing of the purported “nuclear underwater attack drone” was part of a three-day exercise that simulated nuclear attacks on unspecified South Korean targets, which also included cruise missile launches on Wednesday.

KCNA said that the drills were supervised by North Korean leader Kim Jong-un, who condemned the US-South Korean drills as invasion rehearsals and vowed to make his rivals “plunge into despair”.

The drone is named “Haeil,” a Korean word meaning tidal waves or tsunamis. The North’s official Rodong Sinmun newspaper published photos of Kim smiling next to a large torpedo-shaped object at an unspecified indoor facility, but didn’t identify it.

Other photos published with the same article showed sea-surface tracks supposedly caused by the drone’s underwater trajectory and a pillar of water exploding up into the air, possibly caused by what state media described as an underwater detonation of a mock nuclear weapon carried by the drone.

 - AP