text: Operations During Armed Conflict
  6-150. Area security is a type of security operation conducted to protect friendly forces, lines of
  communications, and activities within a specific area (ADP 3-90). The security force may be protecting the
  civilian population, civil institutions, and civilian infrastructure with a unit’s assigned area.
  6-151. Cover is a type of security operation done independent of the main body to protect them by fighting
  to gain time while preventing enemy ground observation of and direct fire against the main body (ADP 3-90).
  A force tasked to cover may do so offensively or defensively.
  6-152. Guard is a type of security operation done to protect the main body by fighting to gain time while
  preventing enemy ground observation of and direct fire against the main body (ADP 3-90). Units performing
  a guard cannot operate independently. They rely on fires and functional and multifunctional support assets
  of the main body. A force tasked to guard may do so offensively and defensively.
  6-153. Screen is a type of security operation that primarily provides early warning to the protected force
  (ADP 3-90). Screens provide less protection than guards or covers. Screen missions are defensive in nature
  and accomplished by establishing a series of observation posts and patrols to ensure observation of the
  assigned area. The screen force gains and maintains enemy contact consistent with the operation order and
  destroys or repels enemy reconnaissance units by conducting counter-reconnaissance.
  6-154. The screen, guard, and cover security operations provide increasing levels of combat power and
  increasing levels of security for the main body. Area security preserves freedom to move reserves, position
  fire support means, protect C2 systems, and conduct sustainment operations. Commanders balance the
  combat power employed for security against the requirements of the main and supporting efforts.
  6-155. All maneuver forces are capable of conducting security operations. All Army BCTs conduct security
  operations as part of their mission-essential task list, while maneuver enhancement brigades, when properly
  task-organized, support theater army, corps, and divisions by conducting screens and area security throughout
  its assigned area of operations. Habitual support relationships with attachments and established standard
  operating procedures facilitate unity of effort and efficiency during security operations spanning multiple
  echelons of divisions and corps.
  6-156. Successful security operations in any domain depend on properly applying five fundamentals. These
  fundamentals are—
  (cid:122) Provide early and accurate warning.
  (cid:122) Provide reaction time and maneuver space.
  (cid:122) Orient on the protected force, area, or facility.
  (cid:122) Perform continuous reconnaissance.
  (cid:122) Maintain enemy contact.
  (See ADP 3-90 for additional information on the conduct of security operations.)
  TROOP MOVEMENT
  6-157. Troop movement is the movement of Soldiers and units from one place to another by any available
  means (ADP 3-90). Units perform troop movements using different methods, such as dismounted foot
  marches, mounted marches using tactical vehicles, or air, rail, and water means in various combinations. The
  method employed depends on the situation, the size and composition of the moving unit, the distance the unit
  must cover, the urgency of execution, and the condition of the troops. It also depends on the availability,
  suitability, and capacity of the different means of transportation. Troop movements over extended distances
  have extensive sustainment considerations.
  RELIEF IN PLACE
  6-158. A relief in place is an operation in which, by direction of higher authority, all or part of a unit is
  replaced in an area by the incoming unit and the responsibilities of the replaced elements for the mission and
  the assigned zone of operations are transferred to the incoming unit (JP 3-07.3). Units have three techniques
  for conducting a relief: sequentially, simultaneously, or staggered. A sequential relief occurs when each
  element in the relieved unit is relieved in succession, from right to left, left to right, front to rear, or rear to
  front. A simultaneous relief occurs when all elements are relieved at the same time. A staggered relief occurs