Infantry Drills

3-91: Security

Previous: 3-89: Coordination

3-91. Security in the defense includes all active and passive measures taken to avoid detection by the enemy, deceive the enemy, and deny enemy reconnaissance elements accurate information on friendly positions. The two primary tools available to the platoon leader are observation posts and patrols. In planning for the security in the defense, the platoon leader considers the military aspects of terrain: observation and fields of fire, avenues of approach, key terrain, obstacles and cover, and concealment. He uses his map to identify terrain that will protect the platoon from enemy observation and fires, while providing observation and fires into the engagement area. He uses intelligence updates to increase his situational understanding, reducing the possibility of the enemy striking at a time or in a place for which the platoon is unprepared.

3-92. Current mission commands systems allow mechanized squads to digitally transmit enemy situation and observation reports. This simplifies the reporting process without compromising security. Dismounted observation posts still render reports by frequency modulation radio transmission.

Next: 3-93: Observation Posts

Go Back To: U.S. Army FM 3-21.8: The Infantry Rifle Platoon and Squad