MCRP 12-10B.1, page 273

Appendix C Attacking and Clearing Buildings Offensive operations on urbanized terrain will require Marines to attack and clear buildings. 1. Introduction. At the rifle platoon and squad level, the major offensive tasks for combat in built-up areas are attacking and clearing buildings. This involves: Suppressing defensive fires Advancing Marine assault forces Assaulting buildings Clearing buildings Reorganizing assault forces. To accomplish these tasks, the assaulting unit task organizes into assault, security, and support forces or elements. (See Appendix A) 2. Requirements. There are five interrelated requirements for attacking a defended building: fire support, movement, assault, clearing, and reorganization. Proper application and integration of these requirements reduce casualties and hasten accomplishment of the mission. The proper integration of these requirements are determined by METT-T. For example, larger cities may have high-rise apartment buildings and industrial complexes that are separated by parking areas or parks. Increased fire support may be required to suppress and obscure enemy gunners covering the open terrain and spaces between buildings. Conversely, a built-up area with few open areas can provide numerous covered routes that may decrease fire support requirements. 3. Fire Support. Fire support necessary to advance the assault force may include: Suppressing and obscuring enemy gunners within the objective building(s) and adjacent structures Isolating the objective building(s) with fires to prevent enemy withdrawal, reinforcement, or counterattack Breaching walls en route to and in the objective structure Destroying enemy positions with direct-fire weapons