Fireforce is a variant of the tactic of vertical envelopment of a target by helicopter-borne and parachute infantry developed by the Rhodesian Security Forces during the Rhodesian Bush War. Fireforce counter-insurgency missions were designed to trap and eliminate Zimbabwe African National Liberation Army and Zimbabwe People's Revolutionary Army insurgents before they could flee. Fireforce reacted to enemy ambushes, farm attacks, or observation post (OP) sightings, and could also be called in by trackers or patrols who had made contact with the enemy and then called for reinforcements. Fireforce was first deployed in January 1974, and saw its first action a month later on 24 February 1974.