Military operations and Missions

Most North Korean soldiers are virtually manual workers working on construction sites and farms.

He majority of North Korean soldiers are more accustomed to working with shovels than with rifles. Every spring, soldiers are sent to rural areas to plant rice and corn seeds.
Such an operation takes at least two months. In the fall, they participate in harvests and are sent to construction sites throughout the country all year. Soldiers are engaged in many surprisingly non-military tasks, such as collecting medicinal herbs in the mountains or carrying civilian goods throughout the country. The average North Korean soldier is estimated to be engaged in agricultural or construction work for one-third to half of military service.
Only a few elite units, including those stationed near demilitarized zones, have been excluded from this mission. The Korean People’s Army soldiers are both farmers and construction workers. (Andrey Lankov, North of the DMZ: Essays on Daily Life in North Korea)

According to the following testimony of a former North Korean military defector, Ju Seong-il, North Korea had dispatched troops confidentially to the Vietnam War.

My father was studying abroad at the Russian Flying School when he was young, so he was promoted quickly, and when I was convinced he was the Chief of the Flight Regiment. In addition, his father had participated in the Vietnam War under the secret order of North Korea. Of course, North Korea officially states that no soldiers have participated in the Vietnam War. However, the North Korean army, which saw South Korea dispatching to Vietnam, was secretly sending a small number of talented soldiers to Vietnam for fear of lagging behind in combat experience. (Ju Seong Il “North Korean People’s Army: Barracks in Living Hell”)