text: Fire Support in Depth During Large-Scale Combat Operations
  * Stability operations are often conducted in noncontiguous areas of operation. This can complicate
  the use of FSCMs, the ability to mass and shift fires, and clearance of fires procedures.
  * Fires may be used more frequently to defend key sites than to seize them.
  * Additional planning for the use of precision and near precision munitions and employment of
  additional nonlethal capabilities may be necessary to limit collateral damage.
  * Planning FS to demonstrate capabilities, provide a show of force, or to provide AD fires.
  * An increase in the amount and types of restrictive FSCMs may be appropriate.
  REAR AND SUPPORT AREA OPERATIONS
  6-158. Rear operations are tactical actions behind major subordinate maneuver forces that facilitate
  movement, extend operational reach, and maintain desired tempo (FM 3-0). Support area operations are the
  tactical actions securing lines of communications, bases, and base clusters that enable an echelon’s
  sustainment and command and control (FM 3-0). In large-scale combat operations, a maneuver enhancement
  brigade is assigned to the rear and support area, and it provides support to forces in contact with the enemy.
  Threats In The Support and Rear Area
  6-159. Threats in the support and rear areas are categorized by the three levels of defense required to counter
  them. Any or all threat levels may exist simultaneously. Emphasis on base defense and security measures
  may depend on the anticipated threat level described below:
  * A level I threat is a small enemy force that can be defeated by those units normally operating in
  the echelon support area or by the perimeter defenses established by friendly bases and base
  clusters (ATP 3-91). A level I threat for a typical base consists of a squad-sized unit or smaller
  groups of enemy soldiers, agents, or terrorists.
  * A level II threat is an enemy force or activities that can be defeated by a base or base cluster's
  defensive capabilities when augmented by a response force (ATP 3-91). A typical response force
  is an MP platoon (with appropriate supporting fires); however, it can be a combined arms
  maneuver element. Level II threats consist of enemy special operations teams, long-range
  reconnaissance units, mounted or dismounted combat reconnaissance teams, and partially attrited
  small combat units.
  * A level III threat is an enemy force or activities beyond the defensive capability of both the base
  and base cluster and any local reserve or response force (ATP 3-91). It consists of mobile enemy
  combat forces. Possible objectives for a level III threat include seizing key terrain, interfering with
  the movement and commitment of reserves and artillery, and destroying friendly combat forces.
  The division response to a level III threat is a tactical combat force (TCF). A tactical combat force
  is a rapidly deployable, air-ground, mobile combat unit with appropriate combat support and
  combat service support assets assigned to and capable of, defeating Level III threats, including
  combined arms (JP 3-10). The TCF requires tactical mobility and enough combined arms
  capability to deal with the threats it is likely to face. It should include or be supported by fires,
  aviation, and engineer assets. (FM 3-0). Should the TCF with its supporting artillery be committed,
  the FSO will coordinate with the FSE for additional FS attack/delivery systems as needed to assist
  base, base cluster, or other response forces countering level II or III threats. The TCF will retain
  priority of fires.
  FIRE SUPPORT CONSIDERATIONS
  6-160. With few exceptions, indirect-fire assets should not be employed against a level I threat or against
  those level II threat forces that can be defeated by base or base cluster units or by the response force. These
  threats are usually individual or small-unit operations, are of limited scope and duration, and provide too
  fleeting a target for successful engagement by indirect-fire assets. Considerations that affect the application
  of FS in the rear area include:
  * The reduction of FS capabilities to the MBA.
  * The responsiveness of the available weapons systems.
  * The precision and collateral damage effects of the weapon systems.