9 th ▁Infantry ▁Regiment ▁and ▁ 7 th ▁R anger ▁Group ▁through ▁the ▁sw amp ▁lands ▁around ▁ Đ ứ c ▁Hu ệ ▁towards ▁the ▁Camb od ian ▁border , ▁and ▁had ▁V NA F ▁air plan es ▁attack ▁positions ▁of ▁ 5 th ▁N VA ▁Division ▁units . ▁In ▁the ▁meant ime , ▁he ▁re lied ▁on ▁two ▁Regional ▁Force ▁batt al ions ▁belonging ▁to ▁IV ▁Corps ▁to ▁move ▁from ▁M ộ c ▁H ó a ▁up ▁north ▁to ▁establish ▁blocking ▁positions ▁on ▁the ▁south western ▁edge ▁of ▁the ▁ 5 th ▁N VA ▁Division ' s ▁log ist ical ▁base ▁and ▁assembly ▁area . ▁On ▁ 2 8 ▁April , ▁General ▁Hi ế u ▁launched ▁eleven ▁batt al ions ▁into ▁the ▁battle ground ▁to ▁conduct ▁pre lim inary ▁operation ▁in ▁prepar ation ▁of ▁the ▁main ▁off ensive . ▁ ▁The ▁next ▁morning , ▁three ▁arm ored ▁squad rons ▁of ▁the ▁III ▁Corps ▁Ass ault ▁Task ▁Force ▁r ushed ▁across ▁the ▁Camb od ian ▁border ▁from ▁G ò ▁D ầ u ▁H ạ , ▁aim ing ▁directly ▁at ▁ 5 th ▁N VA ▁Division ▁H Q . ▁Meanwhile , ▁a ▁task ▁force ▁compos ing ▁of ▁inf antry ▁and ▁arm or ▁of ▁IV ▁Corps , ▁origin ating ▁from ▁M ộ c ▁H ó a , ▁man eu ver ed ▁across ▁the ▁Camb od ian ▁border ▁into ▁the ▁Ele ph ant ' s ▁Foot ▁area ▁to ▁threaten ▁the ▁retre at ▁of ▁ 2 7 5 th ▁N VA ▁Regiment . ▁The ▁three ▁arm ored