They also vowed to remain loyal to Kim Jong-un on the occasion of the late founder's birthday, a major holiday in the North. The anniversary, known in North Korea as the "Day of the Sun," falls on Saturday.

North Korean troops' show of their allegiance to the ruling Kim family came amid heightened tensions as North Korea is reportedly preparing to carry out its sixth nuclear test and launch an intercontinental ballistic missile after firing a ballistic missile into the East Sea from its eastern coast last week.

Participants at the ceremony included military chief Hwang Pyong-so, widely viewed as the No. 2 man in North Korea and director of the general political bureau of the KPA; Ri Myong-su, the military's chief of general staff; and Pak Yong-sik, minister of the armed forces.

In a speech broadcast live by the North's Korean Central TV, Hwang said the North will "mount a preemptive nuclear attack on South Korea and the United States and wipe them out without traces if they attempt to launch a war of aggression."

During the ceremony, a military band performed and the participants paid homage to the statues of the two late leaders before 21 gun salutes were fired. North Korean soldiers, cadets of the military academies at all levels, and students of the revolutionary schools took part in a parade. (Yonhap)