North Korea says it tested new underwater nuclear attack drone

North Korea claimed Friday it had tested an underwater nuclear attack drone able to unleash a "radioactive tsunami", as it blamed recent US-South Korea exercises for a deteriorating regional security situation.

Pyongyang carried out drills in response this week, the official Korean Central News Agency said, including testing of the new underwater nuclear delivery system.

"This nuclear underwater attack drone can be deployed at any coast and port or towed by a surface ship for operation," the report said.

The weapon's mission is to "stealthily infiltrate into operational waters and make a super-scale radioactive tsunami ... to destroy naval striker groups and major operational ports of the enemy," it added.

North Korean leader Kim Jong Un personally oversaw the tests, KCNA reported, and images released by Pyongyang's Rodong Sinmun newspaper showed a smiling Kim and what appeared to be an underwater explosion.

The agency also said Pyongyang had fired strategic cruise missiles "tipped with a test warhead simulating a nuclear warhead" on Wednesday.

But analysts questioned North Korea's claims.

The idea that Pyongyang has "a nuclear-capable underwater drone should be met with skepticism," said Leif-Eric Easley, a professor at Ewha University in Seoul.

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