Previous: Appendix D: Security
D-1. Infantry platoons and squads conduct security tasks independently or part of a larger force. Security tasks are screen, guard, cover, area security, and local security. These tasks are executed in the larger unit’s security zone (advance, flank, or rear of the main body). Leaders given these tasks or participating in the task of a larger unit must, at a minimum, understand their engagement criteria and whether or not to become decisively engaged. (Refer to FM 3-90-2 for more information.) Security tasks include the following options:
- Screen. Screen is a security task that primarily provides early warning to the protected force. (Refer to FM 3-90-2 for more information.) A screen at platoon level may consist of a combination of observation post and security patrols.
- Guard. Guard is a term with a dual meaning; the difference is the size of the element. When used to refer to individuals, a guard is the individual responsible to keep watch over, protect, shield, defend, warn, or duties prescribed by general orders or special orders. Guards also are referred to as a sentinels, sentries, or lookouts. When used in reference to units, a guard is a security task to protect the main force by fighting to gain time while also observing and reporting information and preventing enemy ground observation of and direct fire against the main body. Units conducting a guard mission cannot operate independently because they rely upon fires and functional and multifunctional support assets of the main body. (Refer to FM 3-90-2 for more information.) A platoon participating in a guard tasks may conduct a combination of observation posts, battle positions, combat patrols, reconnaissance patrols, or movement to contact for protection.
- Cover. Cover is a security task to protect the main body by fighting to gain time while also observing and reporting information and preventing the enemy ground observation and direct fire against the main body for an extended period of time. (Refer to FM 3-90-2 for more information.) Ordinarily only brigade -sized and larger elements have the assets necessary to conduct this type of security operation.
- Area security. Area security is a security task conducted to protect friendly forces, installations, routes, and actions within a specific area. (Refer to FM 3-90-2 for more information.) During conventional operations area security refers the security measures used in friendly controlled areas. Many of the tasks traditionally associated with stability and small scale contingencies fall within the scope of area security. These include road blocks, traffic control post, route security, convoy security, and searches.
- Local security. Local security is a security task that includes low-level security activities conducted near a unit to prevent surprise by the enemy. (ADRP 3-90) Local security measures are the same as those outlined for exterior guards in FM 22-6.
D-2. The screen, guard, and cover are the security measures used primarily by battalion-sized units to secure themselves from conventional enemy units. These measures, respectively, contain increasing levels of combat power and provide increasing levels of security of the main body. Along with the increase of combat power, there is an increase in the unit’s requirement to fight for time, space, and information on the enemy. Conceptually, the measures serve the same purpose as the local security measures by smaller units. For example, a battalion will employ a screen for early warning while a platoon or squad will emplace an observation post. The purpose is the same, early warning, only the degree and scale are different.
D-3. Local and area security are related since they both focus on the enemy threat within a specified area. Again, the difference is one of degree and scale. Local security is concerned with protecting the unit from enemy in the immediate area, whereas area security is concerned with enemy anywhere in the leader’s area of operation.