Fire and movement, or fire and maneuver, is the basic modern military low-level unit tactic used to maneuver on the battlefield in the presence of the enemy, especially when under fire. It involves heavy use of all available cover, and highly-coordinated exchanges of rapid movement by some elements of the squad or platoon while other elements cover this movement with suppression fire. It is used both to advance on enemy positions as part of an attack, or withdrawal from current positions under attack by the enemy. The moving and supporting (suppressing) elements may be teams or individuals, and may quickly and continuously exchange roles until the entire unit completes the maneuver objective. Some members will specialize more in different roles within fire and movement as fits their range,