North Korea says it tested underwater nuclear attack drone

North Korea said Friday that it had tested an underwater nuclear attack drone in response to a naval exercise by South Korea, the United States and Japan.

North Korea’s military said it conducted the test of the “Haeil-5-23” in the country’s eastern waters. It did not specify the date the test occurred.

A statement released by the North Korea Ministry of National Defense called the joint drill between South Korea, the U.S. and Japan “frantic” and “provocative.” The statement claimed the operation further destabilized the region and is “seriously threatening the security” of North Korea.

“Our army’s underwater nuke-based countering posture is being further rounded off and its various maritime and underwater responsive actions will continue to deter the hostile military maneuvers of the navies of the United States and its allies,” the military added in a statement highlighted by KCNA Watch.

The statement denounced the United States “and its followers” and “sternly warn them of the catastrophic consequences” of threatening the country’s security.

South Korea’s Defense Ministry denounced North Korea’s recent tests as violating United Nations Security Council resolutions and a threat to peace for the Korean Peninsula and around the world, The Associated Press reported.

The drone, which is designed to destroy naval vessels and ports, was first tested last year and is among a broad range of nuclear-capable weapons North Korea has displayed in recent years, AP noted.

The underwater test came just days after North Korean leader Kim Jong Un dismantled North Korean government organizations that were in charge of managing relations with South Korea. Kim took aim at South Korea and the U.S. for escalating tensions and urged the North Korean assembly to rewrite its constitution to label South Korea as the North’s “No. 1 hostile country,” The Hill previously reported.

North Korea earlier this week also claimed to have successfully test-fired a hypersonic missile equipped with a hypersonic, maneuverable warhead that is a more lethal threat than intercontinental ballistic missiles. China and Russia each have them in their arsenal, and the U.S. is racing to develop its own.