Suppressive fire is typically used as covering fire against the enemy in the close combat zone. However, suppressive fire delivered by artillery and other indirect fire means can be used to suppress targets of any type, most notably as counter-battery fire against indirect fire units. NATO also defines 'suppression of enemy air defenses' (SEAD), which has a broader definition and includes materiel damage. An important consideration in the application of suppressive fire from indirect fire systems (e.g. mortars, artillery and ships) and aircraft is the safety of the attacking troops. Fragmenting munitions are indiscriminate and potentially lethal in all directions around the point of burst although the pattern and extent of the lethal area depends on several variable factors, some specific to each situation.