In the Plan Challe, the French army attacked the FLN fighters. The French sent reserve units and conscript units to defend places where they would not have to be moblie. For example protecting roads. This way, regular French army units could perform search and destroy missions in the mountains where guerrilla fighters were hiding. They used helicopters to move special mobile units composed of elite troops such as Foreign Legionnaires, paratroopers, marines, special commandos units, and air mobile regulars. These elite forces never exceeded more than 20,000 soldiers.