Marching fire, also known as walking fire, is a military tactic—a form of suppressive fire used during an infantry assault or combined arms assault. Advancing units fire their weapons without stopping to aim, in an attempt to pin down enemy defenders. Marching fire usually ends with an infantry charge to engage the enemy in close combat. The tactic requires ample ammunition and rapid-fire weapons. It differs from fire and movement in that the attacking force advances in unison rather than leapfrogging forward in alternating groups.