text: Chapter 13
  TIME THE SECURITY FORCE MUST BE ESTABLISHED
  13-26. Main body units determine when to establish their security forces. They base their decision on the
  actions of the main body and enemy forces. They allow enough time for their security force to move and
  occupy their security areas to prevent enemy forces from penetrating those security areas undetected. The
  mission variables influence how these security forces deploy and occupy their positions. Units position their
  security forces so they can continue performing security tasks after completing their initial mission. This
  frequently occurs when a reconnaissance mission halts at a designated phase line.
  CRITERIA FOR ENDING THE SECURITY MISSION
  13-27. Security missions are usually time or event driven and determined by the security force’s higher
  headquarters. The commander gives the unit the necessary details through the commander’s security
  guidance. The criteria for ending a security mission can be an action by the main body (such as completing
  a specific mission), a fixed time (for example, not allowing an enemy force to penetrate a PL for two hours),
  or criteria based on the enemy force (such as its size). Security force units normally require the permission
  of their main body commanders to withdraw behind their rear boundaries to terminate their security missions.
  AUGMENTATION OF SECURITY FORCES
  13-28. The assignment of security areas larger than the areas of influence of these security forces’ organic
  weapons requires the augmentation of those forces’ organic combat power. Main body units are responsible
  for reinforcing their security forces in this case. They place additional maneuver and functional and
  multifunctional support assets under the operational control or in support of their security force. Units
  commonly attach engineers, chemical, civil affairs, or EMS reconnaissance elements to their security forces
  at the company or troop level. Additionally, any unique security mission requirements may require assets not
  organic to these security forces.
  13-29. Information collection assets greatly enhance the performance of security tasks. These assets
  conduct rapid surveillance of large areas to detect enemy presence. Data from remote sensors, UAS sensors,
  unattended ground sensors, signals intelligence systems, and downlinks from national assets can expand the
  areas under surveillance and cue security forces. Rotary-wing aircraft detect and report enemy forces at
  extended ranges with thermal imaging and other advanced detection equipment. This permits security force
  units to concentrate their forces on likely enemy avenues of approach, NAIs, targeted areas of interest, and
  restrictive terrain that degrades sensor performance. They employ their information collection assets to detect
  enemy force movements. This gains time to reposition their security forces and mass other assets to counter
  enemy actions. Main body units request higher echelon support if their security force intelligence assets
  cannot provide sufficient advance warning.
  SPECIAL REQUIREMENTS OR CONSTRAINTS
  13-30. Main body commanders may impose special requirements or constraints, including engagement,
  disengagement, and bypass criteria (located in the commander’s security guidance). They may order their
  security forces to avoid decisive engagements or avoid falling below a certain combat strength. Units may
  be willing to accept a lesser degree of security, which results from either the loss of more terrain or reduced
  preparation time by the main body, to preserve their security forces for later use. The opposite is also true,
  main body commanders may be willing to risk their security force becoming decisively engaged to create
  time for the main body.
  FIRES PLANNING
  13-31. Main body units request nonlethal effects and position fire support assets to support screen and guard
  forces. They allocate additional artillery to support covering forces. If they assign their security forces wide
  assigned areas, units may have to position fire support assts and other nonlethal capabilities to provide
  effective coverage of only the most likely enemy avenues of approach. This is particularly important for a
  screen because often the screening force relies on indirect fire to delay or disrupt enemy forces. Providing
  adequate indirect fire support to their security forces may require main body units to position their artillery
  systems well forward in the main body formation.