North Korea was staging a paramilitary parade in Pyongyang on Saturday to mark the 75th anniversary of the regime's founding day, an informed source said.

The event began at midnight following a pre-parade ceremony held Friday night, the source said, without elaborating.

Details of the event, including whether leader Kim Jong-un attended the parade and what weapons were displayed, were not immediately known.

The nighttime event marks the third military parade North Korea has staged this year alone, with the latest one taking place in July on the occasion of the 70th anniversary of the signing of the 1950-53 Korean War armistice.

The latest military parade comes as the North has been seeking to strengthen ties with China and Russia and double down on its weapons development in the wake of strengthening security cooperation among South Korea, the United States and Japan.

China's foreign ministry said a delegation, led by Vice Premier Liu Guozhong, will visit North Korea from Friday for celebrations of the anniversary.

The militia parade came as North Korea launched a newly built "tactical nuclear attack submarine" capable of carrying out an underwater nuclear attack, with leader Kim Jong-un vowing to "further strengthen the state nuclear deterrence."

The North Korean leader is reportedly set to travel to Vladivostok, Russia, to meet with Russian President Vladimir Putin next week and discuss a possible arms deal. (Yonhap)