A TV screen shows an image of DPRK leader Kim Jong Un during a news program at the Seoul Railway Station in Seoul, South Korea, Friday, March 24. (AP)

The Democratic People's Republic of Korea's official Korean Central News Agency (KCNA) reported that the DPRK tested an underwater drone that can carry nuclear weapons and launched a test warhead without nuclear charge from it in the Sea of Japan.

The drone was reportedly put in the waters off South Hamgyong province on Tuesday. Furthermore, it cruised for over 59 hours at a depth of 80 to 150 meters and was detonated off its east coast, KCNA added.

KCNA said the weapon can unleash a "radioactive tsunami".

It further stressed that "the drone is designed to attack enemy vessels and ports by setting off a super-scale radioactive wave."

According to the news agency, Kim Jong Un, the country's leader, personally oversaw the test.

Tensions on the Korean peninsula have been escalating, as the US and South Korea completed what was described as the largest joint field exercises in five years on Wednesday.

Earlier this month, Pyongyang said the "irresponsible acts" of Washington and Seoul will take the region "to a very critical and uncontrollable phase."

It is worth noting that the US conducted the fifth round of combined air drills by sending the nuclear strategic bomber B-52 on March 6, and on March 13, the massive US-South Korea joint military exercise Freedom Shield began. This was done despite the worsening military and political conditions on the Korean peninsula and in the surrounding area.