 During the planning for the invasion of South Korea in the years before the war, the North Korean leadership began to create large numbers of commando and special forces units to send south.These units subverted South Korean authority before and during the war with terror campaigns, sabotage and inducing rebellions in ROK military units.Hundreds of commandos were sent to South Korea in this fashion, and by the end of the war up to 3,000 of them had been trained and armed.