North Korea, irate over U.S.-South Korea war games, claims to test sea drone capable of unleashing "radioactive tsunami"

North Korea claimed Friday to have tested an underwater attack drone capable of unleashing a "super-scale radioactive tsunami" if armed with a nuclear warhead. The brazen claim — which many experts doubt  — was part of the Kim Jong Un regime's angry response to the latest joint war games by the U.S. and South Korean militaries.

The North released pictures of Kim admiring what the country's official news service said was the new underwater drone, and others purportedly showing it at sea, along with an underwater explosion. The regime claimed...