text: _________________________________________________________________________________Chapter 4
  Security Force
  4-58. The security force conducts activities to prevent or mitigate the effects
  of hostile actions against the overall operational-level command and/or its
  key components. If the commander chooses, he may charge this security force
  with providing force protection for the entire AOR, including the rest of the
  functional forces; logistics and administrative elements in the support zone;
  and other key installations, facilities, and resources. The security force may
  include various types of unitssuch as infantry, SPF, counterreconnaissance,
  and signals reconnaissance assetsto focus on enemy special operations and
  long-range reconnaissance forces operating throughout the AOR. It can also
  include internal security forces units allocated to the operational-level com-
  mand, with the mission of protecting the overall command from attack by
  hostile insurgents, terrorists, and special operations forces. The security
  force may also be charged with mitigating the effects of weapons of mass
  destruction (WMD). The security force commander can be given control over
  one or more reserve formations, such as the antilanding reserve.
  Counterattack Forces
  4-59. In a defensive operation with a planned counterattack scheme (typically in
  a maneuver defense), the operational-level commander designates one or
  more counterattack forces. He also shifts his task organization to create a
  counterattack force when a window of opportunity opens that leaves the enemy
  vulnerable to such an action. At the operational level, the counterattack force
  may be a multi-division force with the mission to destroy a major enemy for-
  mation that is exposed. The operational-level commander uses counterattack
  forces to complete the defensive mission assigned and regain the initiative
  for the offense. The counterattack force can have within it fixing, assault,
  and exploitation forces (as outlined in Chapter 3).
  Types of Reserves
  4-60. At the commander’s discretion, forces may be held out of initial action
  so that he may influence unforeseen events or take advantage of developing
  opportunities. He may employ a number of different types of reserve forces of
  varying strengths, depending on the situation.
  4-61. Maneuver Reserve. The size and composition of a reserve force is
  entirely situation-dependent. However, the reserve is normally a force
  strong enough to respond to unforeseen opportunities and contingencies at
  the operational level. A reserve may assume the role of counterattack
  force to deliver the final blow that ensures the enemy can no longer conduct his
  preferred operation.
  4-62. A reserve force is given a list of possible missions for rehearsal and
  planning purposes. The staff assigns to each of these missions a priority,
  based on likelihood that the reserve might be called upon to execute that
  mission. Some missions given to the reserve may include
  • Conducting a counterattack. (The counterattack goal is not limited to
  destroying enemy forces, but may also include recovering lost positions
  or capturing positions operationally advantageous for subsequent
  combat actions.)