text: Security Operations
  fire support weapons, deploying over a narrower front than a comparable-sized screening force to permit
  concentrating combat power.
  13-73. Units employ a guard when enemy contact is expected, and they require additional security beyond
  that provided by a screen. The multiple requirements of the guard mission often occur simultaneously over
  large areas. While the guard force’s exact size is determined by prevailing mission variables, table 13-1 on
  page 13-5 provides guidance on the size of an echelon’s guard force.
  13-74. The three types of guard operations are advance, flank, and rear guard. Commanders can assign a
  guard mission to protect either a stationary or a moving force.
  13-75. A unit conducting a guard performs tasks within its capabilities unless ordered otherwise. If a unit
  lacks the time, lacks resources, or is unable to complete all tasks, it must inform the higher echelon assigning
  the mission of the shortfall and request guidance on which tasks to complete or the priority of tasks. Guard
  tasks, within capability are to—
  * Detect and report all enemy elements attempting to pass through the guard, both ground and aerial,
  and provide the protected force commander early warning of enemy activities.
  * Conduct counterreconnaissance to destroy or defeat all enemy reconnaissance elements according
  to engagement criteria. Must prevent ground observation and direct fire against the main body.
  * Maintain contact with the protected force and other forces operating on its flanks.
  * Maintain contact with enemy forces and report activity in the assigned area.
  * Maintain observation of avenues of approach that affect the protected forces mission.
  * Locate and identify the lead elements that indicate the enemy’s main attack, as prescribed in the
  enemy’s order of battle based upon IPB (when facing an echeloned enemy force).
  * While displacing, determine the direction of enemy movement, maintain contact, and report threat
  activities.
  * While displacing, impede and harasses the enemy, within capability, to provide the protected force
  commander with additional time and maneuver space.
  * Cause the enemy main body to deploy prematurely.
  * Prevent visual contact and direct fire against the protected force.
  * Deny the enemy information about the size, strength, composition, and objective of the main body.
  13-76. If a guard turns into a meeting engagement—
  * Destroy enemy reconnaissance and lead elements of the main body.
  * Determine the location of enemy assailable flanks.
  * Fix enemy forces to allow the main body to maneuver around enemy strengths or through
  weaknesses.
  Organization of a Guard Force
  13-77. Whether the guard force is stationary or moving, the types of guard missions, knowledge of the
  terrain, and enemy dictate the task organization of the guard force. The guard force commander normally
  organizes the guard force as an area defense, a delay, a zone reconnaissance, or a movement to contact.
  Control Measures
  13-78. Units use control measures to control the operations of guard forces in the security area. The mission
  also influences the size of the assigned areas given to subordinate elements. For example, a movement to
  contact normally occurs across a narrower unit frontage than a zone reconnaissance to allow adequate
  concentration of combat power.
  13-79. Guard force commanders may task subordinate elements to conduct screen missions to the front and
  flanks of the guard force. This provides early warning of enemy forces and helps maintain contact with flank
  forces and any higher echelon security force. An example is a cavalry squadron screen in front of a brigade
  operating as a division advance guard. The presence of a higher echelon security force also influences how