North Korea says it has tested a new kind of military underwater drone that can be equipped with a nuclear warhead. The unmanned underwater vehicle “Haeil” for a nuclear attack could be detonated underwater and thereby trigger a “super large radioactive tsunami”, the state-controlled media reported. The information cannot be independently verified. The largely isolated state is subject to harsh international sanctions for its nuclear weapons and missile programs.

According to the reports, the drone test was carried out as part of a commando exercise from Tuesday to Thursday to draw the enemy’s attention to “a current nuclear crisis”. Strategic cruise missiles were also tested to simulate a nuclear attack. North Korea understands the United States and South Korea as enemies. The military in South Korea had detected the launch of several guided missiles by North Korea on the east coast on Wednesday.

The drone has been described by North Korea as a secret weapon. It can be deployed “stationed on any coast and port or towed by a surface ship,” it said. The test took place on Thursday to practice attacking an enemy port. The test warhead exploded off the east coast at a depth of 80 to 150 meters.

Tensions are currently mounting on the Korean peninsula. The tests are also in response to new US military exercises with South Korea. After an unprecedented series of missile tests last year, North Korea has repeatedly tested nuclear-capable missiles and guided missiles again this year, despite a ban by UN resolutions. The US and South Korea resumed full-scale maneuvers.