MCRP 12-10B.1, page 70

Figure 2-19. Attack of a Building The platoon should organize and practice to move as two forces: a maneuver force and an overwatch force. The maneuver force (normally of one squad on narrow streets or two squads on wide streets) moves forward, scouts danger areas, and closes with the enemy. An overwatch force (the remainder of the platoon and its attached or supporting crew-served weapons), moves behind the maneuver force, secures the platoon’s flanks and rear, and provides direct-fire support when needed. These two forces, can exchange roles from time to time to avoid overfatigue of the maneuver force (Figure 2-20). 2404. Utilization of the Reserve. In the offense, a rifle platoon may be assigned as a reserve. The reserve can be used to reinforce and attack or exploit success. Reserves are normally held at the company level. Military Operations on Urbanized Terrain 2-38