one main OP and several secondary OPs were established. Runners and occasionally radios were used to communicate between the OPs and the main command post. The OPs were located so that they could observe enemy movement into the ambush and often they would remain in position throughout the ambush in order to report routes of reinforcement and withdrawal by the enemy as well as his maneuver options. Frequently the OPs were reinforced to squad size and served as flank security. The command post was situated in a central location, often on terrain which afforded it a vantage point overlooking the ambush site. Recon methods: Reconnaissance elements observing a potential ambush target on the move generally stayed 300–500 meters away. Sometimes a "leapfrogging" recon technique was used. Surveillance units were echeloned one behind the other. As the enemy drew close to the first, it fell back behind the last recon team, leaving an advance group in its place. This one in turn fell back as the enemy again closed the gap, and the cycle rotated. This method helped keep the enemy under continuous observation from a variety of vantage points, and allowed the recon groups to cover one another. See also Ambush predator Viet Cong and PAVN battle tactics Flanking maneuver Flypaper theory (strategy) List of military tactics Sniper References Extract from Lt Col Anthony B. Herbert's Soldiers handbook US Army Ranger Handbook section 5-14 for ambushes and 6-11 for reaction to ambushes Assault tactics Military tactics Guerrilla warfare tactics Military operations by type