A fireteam or fire team is a small military quaternion sub-subunit of infantry designed to optimise "bounding overwatch" and "fire and movement" tactical doctrine in combat. Depending on mission requirements, a typical fireteam consists of four or fewer members: an automatic rifleman, a grenadier, a rifleman, and a designated team leader. The role of each fireteam leader is to ensure that the fireteam operates as a cohesive unit. Two or three fireteams are organised into a section or squad in co-ordinated operations, which is led by a squad leader.