North Korea claims to have developed a new nuke-ready subaquatic drone that can make a “super-scale radioactive tsunami through an underwater explosion,” according to state media reports Friday. The drone named “Haeil”—the Korean word for “tsunamis” or “waves”—is designed to “stealthily infiltrate into operational waters” before detonating a warhead to wipe out enemy naval groups and ports, Pyongyang’s Korean Central News Agency (KCNA) said. The craft was supposedly tested for almost 60 hours off the east coast of North Korea this week. Kim Dong Yub, a professor at Seoul’s University of North Korean Studies, said the state’s claims were impossible to verify, adding that the news was intended to show South Korea that any of its ports could be attacked.