[3] The Combined Action Program was designed to increase the ability of the local Vietnamese militia units to defend their own villages. These units, referred to as Popular Forces, were reinforced by groups of Marines who lived, worked, and conducted operations with their Vietnamese counterparts. A Combined Action Company was an organization controlling several Marine squads which served with different Combined Action Platoons. Combined Action Company Oscar (CACO) was the unit operating in the Khe Sanh area. A Regional Forces company was comprised of local South Vietnamese soldiers along with their American and ARVN advisors who were under the operational control of the Vietnamese Province Chief. [4] The III MAF and enemy operations during the period of the NVA/VC winter-spring offensive (1966-1967) will be the subject of a separate monograph prepared by the Historical Branch. [5] The diversionary attacks were all launched apparently on schedule. On 27 and 28 April, the previously mentioned Marine fire support and supply bases were hit by some 1,200 rocket, artillery, and mortar rounds. Route 9 was cut in several places. The Special Forces Camp at Lang Vei was attacked and severely mauled on 4 May. Only the main effort was detected and subsequently thwarted. [6] Marine losses were 155 killed and 425 wounded. PART II THE LULL BETWEEN THE STORMS With the departure of the 3d Marines, a relative calm prevailed at Khe Sanh for the remainder of the year. Although occasional encounters and sightings indicated that the Communists still had an interest in the area, there was a marked decrease in large unit contacts and the tempo of operations slackened to a preinvasion pace. Such was not the case in other portions of Quang Tri Province. During the summer and fall of 1967, the center of activity shifted to the eastern DMZ area. After being battered and thrown for a loss on their end sweep, the Communists concentrated on the middle of the line again. With an estimated 37 battalions poised along the border, the NVA constituted a genuine threat to the northernmost province. At times as many as eight Marine battalions were shuttled into the area for short-term operations and three or four were there full time, but the enemy's intensified campaign created a demand for more troops. As a result, General Westmoreland was forced to make major force realignments throughout South Vietnam to satisfy the troop requirements in I Corps.(14)