text: Chapter 5
  Security Operations
  Security operations are operations to provide early and accurate warning of enemy
  operations, to provide the force being protected with time and maneuver space within
  which to react to the enemy, and to develop the situation to allow commanders to
  effectively use their force. Security is inherent in all operations and is always the first
  priority of work. Commanders use continual reconnaissance and the development of
  information requirements to provide security. Commanders follow the five
  fundamentals of security during security operations to ensure early and accurate
  warning of enemy forces. Security operations provide reaction time and maneuver
  space to develop the situation and determine the most effective use of force to
  neutralize, defeat, or destroy enemy forces. There are four types of security operations:
  screen, guard, cover, and area security. Each security type provides varying levels of
  protection to the main body. The commander weighs operational and mission variables
  with the end state to select the appropriate security type.
  SECTION I – SECURITY BASICS
  5-1. Security is an essential part to all BCT operations. Maneuver units perform security missions as part
  of a larger security force or operate independently with task-organized attachments. The main difference
  between security operations and reconnaissance operations is that security operations orient on the protected
  force, area, or facility to be protected, while reconnaissance is enemy, infrastructure, terrain and weather
  effects, and society oriented. However, security operations cannot be divorced from reconnaissance missions
  as one of the fundamentals of security is to perform continuous reconnaissance.
  5-2. Security operations prevent enemy reconnaissance assets from determining friendly locations,
  strengths, and weaknesses. Every tactical echelon requires a specially trained organization that can execute
  security missions to preserve freedom of action for the main body.
  SECURITY
  5-3. Security operations provide information about the enemy and terrain while preserving the combat
  power of friendly forces. Security operations provide information about the size, composition, location, and
  the enemy forces’ direction of movement. Information collected by the squadron gives the main body
  commander time to react and maneuver to prepare for future operations or to deploy to engage the enemy.
  Security prevents the enemy from surprising the main body, which allows the commander to preserve the
  combat power of maneuver forces and mass effects and combat power at the decisive point in time. (Refer
  to FM 3-90-2 for more information.)
  5-4. Security along a common boundary with another friendly unit is the responsibility of the unit assigned
  to that zone or sector. Liaison with the protected force is critical during security operations. Constant
  communication and liaison ensures both the security force and the protected force remain informed of the
  full situation and maintains synchronized operations.