text: Army Tactics
  operations take advantage of the local security measures performed by all units regardless of their location
  in the assigned area. (See ADP 3-37 for more information on the variations of area security.)
  1-206. A unit develops specific rules of engagement when conducting area security, particularly when
  civilians are present. However, commanders remain responsible for protecting the force, and they consider
  this responsibility when establishing rules of engagement. They explain restrictions on conducting operations
  to ensure everyone understands those restrictions. Soldiers must understand that their actions may have far-
  reaching positive or negative effects. Commanders iterate that media and adversaries can quickly exploit
  their Soldiers’ actions, especially the way they treat civilians.
  1-207. Sometimes area security forces must retain readiness over long periods without contact with enemy
  forces. This occurs most often when the enemy special purpose forces or insurgents are overmatched. Forces
  conducting area security should not develop a sense of complacency, even if the enemy force appears to have
  ceased operations in the secured area. Additionally, friendly forces should be mindful of mines and booby
  traps in these situations. Successful units assume that the enemy force regularly observes friendly operations
  to identify routines, weak points, and lax security for the opportunity to strike with minimum risk. This
  requires leaders to maintain vigilance and discipline in their Soldiers to preclude that opportunity from
  developing.
  Operations Security
  1-208. Operations security is a capability that identifies and controls critical information, indicators of
  friendly force actions attendant to military operations, and incorporates countermeasures to reduce the risk
  of an adversary exploiting vulnerabilities (JP 3-13.3). Operations security (OPSEC) is applied throughout all
  operations to protect any information or activities of friendly elements. The practice of OPSEC denies the
  enemy of information that it may use to disrupt or defeat actions by friendly forces.
  1-209. OPSEC is not only concerned with protecting planning and preparation activities, but also
  encompasses applying effective field craft, camouflage, concealment, and masking. These techniques deny
  and disrupt the enemy’s ability to gain information through reconnaissance and surveillance. It includes
  explaining to Soldiers methods the enemy uses to find and target their cell phones, gather geo-location tags
  from personal photos, and collect information from posts to social media. Other examples include how all
  lead-up activities—to include pre-combat checks and pre-combat inspections, vehicle loading, and
  modifications—can indicate future movements or operations and can provide enemy forces with an initial
  understanding of friendly force activities.
  1-210. A units OPSEC program and any deception or survivability efforts should conceal the location of
  the friendly objective, the main effort, the disposition of forces, and the timing of the offense from enemy
  forces or mislead them regarding this information. These measures prevent enemy forces from launching
  effective spoiling attacks.