text: FM 7-100.1________________________________________________________________________________
  Disruption Force
  4-52. The size and composition of forces in the disruption zone depends on
  the level of command involved, the commander’s concept of operations, and
  the circumstances in which the unit adopts the defense. An operational-level
  disruption force has no set organization but may be as large as a multi-division
  OSC or consist only of SPF teams to direct reconnaissance fires and conduct
  direct action. The operational-level commander will always make maximum use
  of stay-behind forces and affiliated forces existing within his AOR. Subordinate
  commanders can employ forces in a disruption zone role independent of the
  operation plan only with approval of the operational-level commander.
  4-53. A disruption force has no set order of battle, but may contain
  • Ambush teams (ground and air defense).
  • SPF teams.
  • RISTA assets and forces.
  • Counterreconnaissance forces.
  • Artillery systems.
  • Target designation teams.
  • Affiliated forces (such as terrorists, insurgents, criminals, or special police).
  • Antilanding reserves.
  4-54. The purpose of the disruption force is to prevent the enemy from
  conducting an effective attack. The disruption force does this by initiating
  the attack on components of the enemy’s combat system. Successful attack of
  designated components or subsystems begins the disaggregation of the
  enemy’s combat system and creates vulnerabilities for exploitation in the
  battle zone. Skillfully conducted disruption operations will effectively deny
  the enemy the synergy of effects of his combat system.
  4-55. The disruption force may also have a counterreconnaissance mission.
  It may selectively destroy or render irrelevant the enemy’s RISTA forces.
  There will be times, however, when the OPFOR wants enemy reconnaissance
  to detect something that is part of the deception plan. In those cases, the dis-
  ruption force will not seek to destroy all of the enemy’s RISTA assets.
  Main Defense Force
  4-56. The main defense force is the component of the operational-level command
  that is charged with execution of the defensive mission. It operates in the battle
  zone to accomplish the purpose of the operation (destroy, preserve, or deny).
  Protected Force
  4-57. In a defense to preserve, the protected force is the force being kept from
  detection or destruction by the enemy. Protection can be afforded by C3D
  and/or the actions of other OPFOR units. There is generally some force that
  the OPFOR is trying to protect from enemy observation and fire, to ensure
  that it will still have that force after the current operation is over. At the
  operational level, this force is critical to future operations and the preser-
  vation of the regime. It may be in the battle zone or the support zone.