Force Categories of the FMLN
The FMLN forces were organized into the following categories: strategic mobile forces, special select forces, local guerrilla units, and the clandestine militias, who were also known as "Self-Defense Forces of the Masses."
By the end of the war, the combat forces of the FMLN were organized into a highly structured organization with a number of tiers, according to the nature, mission, and training (both ideological and military) of the force. The highest level for a combatant was to become a member of the special select forces. These were chosen from the best members of the strategic mobile forces or regular forces, who were in turn chosen from among the best members of the local guerrilla units, who were chosen from the best of the clandestine militias, who were recruited from the masses, who were recruited from the local population.
This structuring of forces responded to two concepts of organization. On the one hand they were set up to support the expansion of the subversive organization, and on the other hand they gave operational flexibility to guerrilla tactics in both the rural and urban settings.
The Strategic Mobile Forces (SMF) were the most important category of FMLN force. They were composed of permanent units of columns, companies, and battalions. The members of these units had received thorough training in both regular and irregular warfare operations. The vast majority of the SMF members were battle-hardened veterans with extensive experience. When not operating as full units, the SMF forces were