North Korea claims to have tested a purported underwater nuclear attack drone in response to a combined naval exercise between South Korea, the United States and Japan this week.

The nation continues to blame its rivals for raising tensions in the region.

The alleged drone test came days after North Korean leader Kim Jong Un declared he would scrap his country’s long-standing goal of a peaceful unification with South Korea and that his country would rewrite its constitution to define South Korea as its most hostile foreign adversary.

Tensions on the Korean Peninsula are at their highest point in years with Mr Kim accelerating weapons demonstrations and threatening nuclear conflict and the US and its Asian allies responding by strengthening their combined military exercises.

Koreas Tensions
A naval exercise carried out in the Korean Peninsula by the US, South Korea and Japan (South Korea’s joint chiefs of staff via AP)

North Korea’s alleged nuclear attack drone, which the North first tested last year, is among a broad range of weapon systems demonstrated in recent years as Mr Kim expands his arsenal of nuclear-capable weapons.

South Korea’s military has insisted the North has exaggerated the capabilities of the drone, which is supposedly designed to carry out strikes on enemy vessels and ports.

The North’s military said it conducted the test in the country’s eastern waters in response to the US, South Korean, and Japanese naval drills, which wrapped up its three-day run on Wednesday in waters south of Jeju island.

“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 manoeuvres of the navies of the US and its allies,” the North’s defence ministry said in a statement.

“We strongly denounce the US and its followers for their reckless acts of seriously threatening the security of the DPRK (Democratic People’s Republic of Korea) from the outset of the year and sternly warn them of the catastrophic consequences to be entailed by them.”