 The North Vietnamese response to the incursion was to avoid contact with allied forces and , if possible , to fall back westward and regroup . PAVN forces were well aware of the planned attack and many COSVN / B @-@ 3 Front military units were already far to the north and west conducting operations against the Cambodians when the offensive began . During 1969 PAVN logistical units had already begun the largest expansion of the Ho Chi Minh trail conducted during the entire conflict . As a response to the loss of their Cambodian supply route , North Vietnamese forces seized the <unk> towns of <unk> and <unk> during the year , pushing what had been a 60 @-@ mile ( 97 km ) corridor to a width of 90 miles ( 140 km ) and opening the entire length of the Kong River system into Cambodia . A new logistical command , the <unk> Transportation Group , was created to handle logistics in Cambodia and the new " Liberation Route " ran through <unk> <unk> and reached the Mekong at <unk> <unk> . 
