Infantry Drills

FM 3-21.8 – Chapter 7 – Section VIII – Urban Areas

Section VIII – Urban Areas

7-177.  Infantry platoons conduct operations in urban areas using the same principles applicable to other offensive operations. This section explains the general tactics, techniques, and procedures used for a limited attack in an urban area. Depending on the scale of the operation, Infantry platoons or squads may be required to conduct any or all of the find, fix, fight, and follow-through functions. Leaders should expect trouble in the process of determining the exact location of the enemy and should anticipate enemy knowledge of their movements prior to arriving in the objective area.  For a more detailed discussion on urban operations see FM 3-06.11.

Critical Tasks

7-178.  There are a number of critical tasks that need emphasis for Infantry platoons assaulting a building:

– Isolate the building.

– Gain and maintain fire superiority inside and outside the building.

– Gain access to the inside of the building.

– Move inside the building.

– Seize positions of advantage.

– Control the tempo.


7-179.  The compartmentalized nature of urban terrain, limited observation and fields of fire, and the vast amounts of potential cover and concealment mean that defenders can disperse and remain undetected. The origin of enemy gunfire can be difficult to detect, because distance and direction become distorted by structures. The nature of urban conflicts makes it more difficult for leaders to exercise command and control verbally, and for Soldiers to pass and receive information. Situational understanding is normally limited to the platoon’s immediate area.

Isolate the Building

7-180.  The fix function has two aspects: isolating the objective to prevent interference from the outside (while preventing enemy from exiting), and separating forces on the objective from each other (denying mutual support and repositioning). This is accomplished by achieving fire superiority and seizing positions of advantage. If the platoon is conducting a semi-independent assault, it should be organized to accomplish both the fix and finish function.

7-181.  A cordon is a line of troops or military posts that enclose an area to prevent passage. The Infantry platoon normally conducts a cordon as part of a larger unit. It is established by positioning one or more security elements on key terrain that dominates avenues of approach in and out of the objective area. The overall goal is the protection of the maneuver element, and to completely dominate what exits or enters the objective area. This requires a detailed understanding of avenues of approach in the area. There are many techniques used to facilitate isolation including, blocking positions, direct fire (precision and area), indirect fire, roadblocks, checkpoints, and observation posts. The same techniques can be used to cordon and search a small urban area (such as a village) surrounded by other terrain (Figure 7-10).

7-182.  Ideally these positions are occupied simultaneously, but a sequential approach can also be useful. Limited visibility aids can be used in the establishment and security of the cordon. The security element can either surround the area while the maneuver element simultaneously moves in, or it can use a sequential technique in which they use stealth to get into position before the actual assault.

7-183.  Plans should be developed to handle detained personnel. Infantrymen will normally provide security and accompany police and intelligence forces who will identify, question, and detain suspects. Infantry may also conduct searches and assist in detaining suspects, but their principal role is to reduce any resistance that may develop and to provide security for the operation. Use of force is kept to a minimum unless otherwise directed.

Figure 7-10. Isolate the building.

Assault a Building

7-184.  Squads and platoons, particularly when augmented with engineers, are the best organized and equipped units in the Army for breaching protective obstacles; gaining access to buildings; and assaulting rooms, hallways, and stairways. Although there are specific drills associated with fighting in buildings, the overall assault is an operation, not a drill. During planning, the leader’s level of detail should identify each window (aperture, opening, or firing port) in his sector fortifications. He should then consider assigning these as a specific TRP when planning fires.


On 21 July 2003, the 3rd battalion 327 Infantry Regiment and an assault team of elite Special Operations Soldiers from Task Force 20 conducted an assault on a building as part of a raid to kill or capture high value targets.

Surprise, created by leveraging the aspect of time, enabled the leader to control the tempo by creating an initial advantage for the attackers. Instead of sequential actions, the leaders began actions on the objective with the near simultaneous arrival of the assault, support element, and security elements. The assault element arrived at an assault position right outside of the building. The support element occupied three separate support-by-fire positions. Two security elements were organized to establish inner and outer cordons. The first security element isolated the objective by establishing six blocking positions that denied enemy escape and blocked local counterattacks. The second security element formed the outer cordon to prevent a general counterattack and protect the population. With the enemy force found and fixed, an interpreter using a bullhorn requested their quiet surrender. This request was met by gunfire from the objective.

The fight began with the enemy concentrated on the building’s second floor. The support element easily achieved enough fire superiority to enable movement outside the building. With those conditions created, the assault element moved from the assault position to objective and without difficulty seized the building’s first floor. However, once the assault element attempted to go to the second floor, the support element was not able to maintain the fire superiority necessary to facilitate the move. The assault element was also unable to achieve fire superiority. Undeterred, the assault element chanced a move up the stairway only to be beaten back by effective enemy fires resulting in casualties. They attempted several times to gain fire superiority but the defender’s position of advantage gave them the firepower advantage and the assault was halted.

When the leader realized the team would not be able to gain fire superiority from their current locations, he slowed the operation’s tempo down by ordering another element to seize a position of advantage on top of the objective building. Several members of the follow-on force gained access to the roof tops of neighboring houses. From there, they were able to use a supersurface avenue of approach to seize the objective building’s rooftop. From this position of advantage, the Soldiers were able to communicate target locations and monitor munition effects, increasing the support element’s ability to destroy or suppress the enemy.

With fire superiority completely gained outside and inside the building, the assault team successfully renewed its attempt to move to the second floor. Once up the stairs, they quickly eliminated remaining resistance and cleared the remainder of the objective, finishing the fight and accomplishing the mission.

Entering the Building

7-185.  After establishing suppression and obscuration, leaders deploy their subordinates to secure the near side and then, after gaining access, secure the far side. Gaining access to the inside of the building normally requires reducing protective obstacles. Reducing obstacles is discussed at length in Appendix F.

7-186.  Units gain access by using either a top or bottom entry. The entry point is the same thing as a point of penetration for an obstacle breach and as such is a danger area. The entry point will become the focus of fires for any enemy in a position to fire at it. It is commonly referred to as the “fatal funnel.” Leaders ensure they have established measures to ensure the assault team has fire superiority when moving through the fatal funnel. Grenades (ROE determines fragmentation or concussion) are used to gain enough of a window of opportunity until the assault element can employ its small arms fire.

Top Entry

7-187.  The top of a building is ordinarily considered a position of advantage. Entering at the top and fighting downward is the preferred method of gaining access to a building for a number of reasons. First, just as in operations on other types of terrain, it is easier to own the high ground and work your way down than it is to fight your way up when the enemy owns the high ground. Second, an enemy forced down to ground level may be tempted to withdraw from the building and expose himself to the fire of covering units or weapons. Third, the ground floor and basements are normally more heavily defended. Finally, the roof of a building is ordinarily weaker than the walls (and therefore easier to penetrate).

7-188.  Top entry is only feasible when the unit can gain access to an upper floor or rooftop. Rooftops are danger areas when surrounding buildings are higher and forces can be exposed to fire from those buildings. Soldiers should consider the use of devices and other techniques that allow them upper level access without using interior stairways. Those devices and techniques include, but are not limited to, adjacent rooftops, fire escapes, portable ladders, and various Soldier-assisted lifts. For more information on top entry breaching, see FM 3-06.11.

Bottom Entry

7-189.  Entry at the bottom is common and may be the only option available. When entering from the bottom, breaching a wall to create a “mousehole” is the preferred method because doors and windows may be booby-trapped and covered by fire from inside the structure. There are many ways to accomplish this, including employing CCMS, SLM, demolitions, hand tools, machine guns, artillery fire, and tank fire. The actual technique used depends on the ROE, assets available, building structure, and the enemy situation. If the assault element must enter through a door or window, it should enter from a rear or flank position after ensuring the entry point is clear of obstacles.

Secure the Near and Far Side of the Point of Penetration

7-190.  Infantry platoons use the following drill for gaining access to the building. The steps of this drill are very similar to those drills described in Section IX to secure the near and far side of the point of penetration—

– The squad leader and the assault fire team move to the last covered and concealed position near the entry point.

– The squad leader confirms the entry point.

– The platoon leader or squad leader shifts the support fire away from the entry point.

– The support-by-fire element continues to suppress building and adjacent enemy positions as required.

– Buddy team #1 (team leader and automatic rifleman) remain in a position short of the entry point to add suppressive fires for the initial entry.

– Buddy team #2 (grenadier and rifleman) and the squad leader move to the entry point. They move in rushes or by crawling.

– The squad leader positions himself where he can best control his teams.

– Buddy team #2 position themselves against the wall to the right or left of the entry point.

– On the squad leader command of COOK OFF GRENADES (2 seconds maximum), the Soldiers employing the grenades shout, FRAG OUT, and throw the grenades into the building. (If the squad leader decides not to use grenades, he commands, PREPARE TO ENTER—GO!)

– Upon detonation of both grenades (or command GO), the buddy team flows into the room/hallway and moves to points of domination engaging all identified or likely enemy positions.

– Both Soldiers halt and take up positions to block any enemy movement toward the entry point.

– Simultaneously, buddy team #1 moves to and enters the building, joins buddy team #2, and announces, CLEAR.

– The squad leader remains at the entry point and marks it IAW unit SOP. He calls forward the next fire team with, NEXT TEAM IN.

– Once the squad has secured a foothold, the squad leader reports to the platoon leader, FOOTHOLD SECURE. The platoon follows the success of the seizure of the foothold with the remainder of the platoon.

7-191.  When using a doorway as the point of entry, the path of least resistance is initially determined on the way the door opens. If the door opens inward, the Soldier plans to move away from the hinged side. If the door opens outward, he plans to move toward the hinged side. Upon entering, the size of the room, enemy situation, and obstacles in the room (furniture and other items) that hinder or channel movement become factors that influence the number one man’s direction of movement.

Clear a Room

7-192.  The term room in this FM means any enclosed space or partition within a building. Although rooms come in all shapes and sizes, there are some general principles that apply to most room clearing tasks. For clearing large open buildings such as hangars or warehouses, it may be necessary to use subordinate units using a line formation while employing traveling or bounding overwatch. These methods can effectively clear the entire structure while ensuring security.

7-193.  Room clearing techniques differ based on METT-TC, ROE, and probability of noncombatants inside the building. If there are known or suspected enemy forces, but no noncombatants inside the building, the platoon may conduct high intensity room clearings. If there are known or suspected noncombatants within the building, the platoon may conduct precision room clearings. High intensity room clearing may consist of fragmentation grenade employment and an immediate and high volume of small arms fire placed into the room, precision room clearing will not.

7-194.  Room clearing techniques are described using the standard four-man fire team. This does not mean that all four members must enter a room, nor does it mean that more than four men cannot enter. The fire team organization is the baseline from where units adapt to the specific situation. This is because the compartmentalized nature typical of buildings and rooms makes units larger than squads awkward and unmanageable.

7-195.  For this battle drill to be effectively employed, each member of the team must know his sector of fire and how his sector overlaps and links with the sectors of the other team members. No movement should mask the fire of any of the other team members.

7-196.  On the signal, the team enters through the entry point (or breach). As the team members move to their points of domination, they engage all threats or hostile targets in sequence in their sector. The direction each man moves should not be preplanned unless the exact room layout is known. Each man should, however, go in a direction opposite the man in front of him (Figure 7-11). For example:

– #1 Man. The #1 man enters the room and eliminates any immediate threat. He can move left or right, moving along the path of least resistance to a point of domination—one of the two corners and continues down the room to gain depth.

– #2 Man. The #2 man enters almost simultaneously with the first and moves in the opposite direction, following the wall. The #2 man must clear the entry point, clear the immediate threat area, and move to his point of domination.

– #3 Man. The #3 man simply moves in the opposite direction of the #2 man inside the room, moves at least 1 meter from the entry point, and takes a position that dominates his sector.

– #4 Man. The #4 man moves in the opposite direction of the #3 man, clears the doorway by at least 1 meter, and moves to a position that dominates his sector.

7-197.  Once the room is cleared, the team leader may order some team members to move deeper into the room overwatched by the other team members. The team leader must control this action. In addition to dominating the room, all team members are responsible for identifying possible loopholes and mouseholes in the ceiling, walls, and floor. Cleared rooms should be marked IAW unit SOP.

Figure 7-11. Clearing a room.

Moving in the Building

7-198.  Movement techniques used inside a building are employed by teams to negotiate hallways and other avenues of approach. They are similar to movement techniques employed when clearing enemy trenches, which is discussed in Section IX.

Diamond Formation (Serpentine Technique)

7-199.  The serpentine technique is a variation of a diamond formation that is used in a narrow hallway. The #1 man provides security to the front. His sector of fire includes any enemy Soldiers who appear at the far end or along the hallway. The #2 and #3 men cover the left and right sides of the #1 man. Their sectors of fire include any enemy combatants who appear suddenly from either side of the hall. The #4 man (normally carrying the M249 machine gun) provides rear protection against any enemy Soldiers suddenly appearing behind the team.

Vee Formation (Rolling-T Technique)

7-200.  The rolling-T technique is a variation of the Vee formation and is used in wide hallways (Figure 7-12). The #1 and #2 men move abreast, covering the opposite side of the hallway from the one they are walking on. The #3 man covers the far end of the hallway from a position behind the #1 and #2 men, firing between them. The #4 man provides rear security.


Figure 7-12. Diamond and vee formation techniques.

Clearing Hallway Junctions

7-201.  Hallway intersections are danger areas and should be approached cautiously. Figure 7-13 depicts the fire team’s actions upon reaching a “T” intersection when approaching along the “cross” of the “T”. The unit is using the diamond (serpentine) formation for movement (Figure 7-13 A). To clear a hallway—

– The team configures into a modified 2-by-2 (box) formation with the #1 and #3 men abreast and toward the right side of the hall. The #2 man moves to the left side of the hall and orients to the front, and the #4 man shifts to the right side (his left) and maintains rear security. (When clearing a right-hand corner, use the left-handed firing method to minimize exposure [Figure 7-13 B]).

– The #1 and #3 men move to the edge of the corner. The #3 man assumes a low crouch or kneeling position. On signal, the #3 man, keeping low, turns right around the corner and the #1 man, staying high, steps forward while turning to the right. (Sectors of fire interlock and the low/high positions prevent Soldiers from firing at one another [Figure 7-13 C]).

– The #2 and #4 men continue to move in the direction of travel. As the #2 man passes behind the #1 man, the #1 man shifts laterally to his left until he reaches the far corner (Figure 7-13 D).

– The #2 and #4 men continue to move in the direction of travel. As the #4 man passes behind the #3 man, the #3 man shifts laterally to his left until he reaches the far corner. As the #3 man begins to shift across the hall, the #1 man turns into the direction of travel and moves to his original position in the diamond (serpentine) formation (Figure 7-13 E).

– As the #3 and #4 men reach the far side of the hallway, they, too, assume their original positions in the serpentine formation, and the fire team continues to move (Figure 7-13 F).

Figure 7-13. Clearing hallway junctions.


Clearing a “T” Intersection

7-202.  Figure 7-14 depicts the fire team’s actions upon reaching a “T” intersection when approaching from the base of the “T”. The fire team is using the diamond (serpentine) formation for movement (Figure 7-14 A). To clear a “T” intersection—

– The team configures into a 2-by-2 (box) formation with the #1 and #2 men left and the #3 and #4 men right. (When clearing a right-hand corner, use the left-handed firing method to minimize exposure [Figure 7-14 B]).

– The #1 and #3 men move to the edge of the corner and assume a low crouch or kneeling position. On signal, the #1 and #3 men simultaneously turn left and right respectively (Figure 7-14 C).

– At the same time, the #2 and #4 men step forward and turn left and right respectively while maintaining their (high) position. (Sectors of fire interlock and the low/high positions prevent Soldiers from firing at another [Figure 7-14 D]).

– Once the left and right portions of the hallway are clear, the fire team resumes the movement formation (Figure 7-14 E).  Unless security is left behind, the hallway will no longer remain clear once the fire team leaves the immediate area.

Figure 7-14. Clearing a “T” intersection.


Clearing Stairwells and Staircases

7-203.  Stairwells and staircases are comparable to doorways because they create a fatal funnel. The danger is intensified by the three-dimensional aspect of additional landings. The ability of units to conduct the movement depends upon which direction they are traveling and the layout of the stairs. Regardless, the clearing technique follows a basic format:

– The leader designates an assault element to clear the stairs.

– The unit maintains 360-degree, three-dimensional security in the vicinity of the stairs.

– The leader then directs the assault element to locate, mark, bypass, and or clear any obstacles or booby traps that may be blocking access to the stairs.

– The assault element moves up (or down) the stairway by using either the two-, three-, or four-man flow technique, providing overwatch up and down the stairs while moving. The three-man variation is preferred (Figure 7-15).

Figure 9-27. Three-soldier

Figure 7-15. Three-man-flow clearing technique.

Follow Through

7-204.  After securing a floor (bottom, middle, or top), selected members of the unit are assigned to cover potential enemy counterattack routes to the building. Priority must be given initially to securing the direction of attack. Security elements alert the unit and place a heavy volume of fire on enemy forces approaching the unit.

7-205.  Units must guard all avenues of approach leading into their area. These may include—

– Enemy mouseholes between adjacent buildings.

– Covered routes to the building.

– Underground routes into the basement.

– Approaches over adjoining roofs or from window to window.

7-206.  Units that performed missions as assault elements should be prepared to assume an overwatch mission and to support another assault element.

7-207.  To continue the mission—

– Momentum must be maintained. This is a critical factor in clearing operations. The enemy cannot be allowed to move to its next set of prepared positions or to prepare new positions.

– The support element pushes replacements, ammunition, and supplies forward to the assault element.

– Casualties must be evacuated and replaced.

– Security for cleared areas must be established IAW the OPORD or TSOP.

– All cleared areas and rooms must be marked IAW unit SOP.

– The support element must displace forward to ensure that it is in place to provide support (such as isolation of the new objective) to the assault element.

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