North Korea on Friday claimed to have tested an underwater system capable of delivering nuclear weapons. The system, known as Haeil-5-23, is currently under development, state media said. North Korea uses the term “Haeil” to describe underwater attack drones, which it claims can also be equipped with nuclear warheads. Pyongyang didn’t say when the test took place. The rogue state is subject to tough international sanctions due to its nuclear weapons program. The test was reportedly carried out in response to a joint naval exercise involving South Korea, the US and Japan which took place from M…