Pinned down

In military science, suppressive fire (commonly called covering fire) is "fire that degrades the performance of an enemy force below the level needed to fulfill its mission". "Suppression is usually only effective for the duration of the fire". It is one of three types of fire support, which is defined by NATO as "the application of fire, coordinated with the maneuver of forces, to destroy, neutralize or suppress the enemy."

Before NATO defined the term, the British and Commonwealth armies generally used "neutralization" with the same definition as suppression. NATO now defines neutralization as "fire delivered to render a target temporarily ineffective or unusable."

Suppressive fire usually achieves its effect by threatening casualties to individuals who expose themselves to it. Willingness to expose themselves varies depending on the morale, motivation and leadership of the target troops. Suppressive fire is often used as covering fire, defined by NATO as "Fire used to protect troops when they are within range of enemy small arms." This is sometimes called "winning the firefight" in an infantry-only action. However, suppressive fire may be used against indirect firers, enemy air defenses or other military activities such as construction work or logistic activities, or to deny an area to the enemy for a short period of time (it is unsuitable for prolonged area denial due to ammunition supply constraints). Using smoke to 'blind' enemy observation is a form of non-lethal suppression and at night illuminating may be used to suppress enemy activities by denying them the cover of darkness.

Suppression can be delivered by any weapon or group of weapons capable of delivering the required intensity of fire for the required period of suppression. However, the suppressive fire capabilities vary widely because the suppressive effect area varies widely. For example, a rifle or machine gun bullet may only have a suppressive effect within about one metre of its trajectory, whereas a single artillery shell may suppress a few thousand square metres around its burst. Furthermore, sustained suppression over more than a few minutes may be difficult to achieve with small arms fire for logistic reasons, air delivered suppression is similarly affected by payload limits. In contrast, artillery can suppress an area for an extended period.

The purpose of suppression is to stop or prevent the enemy from observing, shooting, moving or carrying out other military tasks that interfere (or could interfere) with the activities of friendly forces. An important feature of suppressive fire is that it is only effective while it lasts and that it has sufficient intensity.

Suppressive fire requires sufficient intensity over the target area, intensity being the suppressive effect per unit of target area per unit of suppression time. Weapons vary widely in their suppressive capabilities, which are the threat signaled by the noise of projectiles in flight and their impact.

...
Wikipedia