The major battle of the enemy's monsoon offensive came during August on Highway 19 at Duc Co CIDG camp near the Cambodian border. Following the loss of the Le Thanh District town in western Pleiku in early June, the VC next seized control of the villages and land development centers in western Pleiku Province. They also continued to build up pressure against the Duc Co Special Forces camp which had been isolated from Pleiku since the loss of Le Thanh District in early June. The VC pressure built up to such an extent that by mid-July the camp was completely surrounded and its patrols driven back within the perimeter defensive wire. Day by day the pressure increased so that by the end of July, in spite of numerous air strikes, the VC had not only surrounded the camp but had dug in mortars and recoiless rifles which were shooting directly into the camp. They next pushed their positions so close to the camp, and their fire became so heavy, that helicopters could not land. With the camp isolated from resupply and helicopter medical evacuation, the corps commander decided to commit the corps' airborne task force to break the siege and destroy the VC surrounding the camp.
Preceded by a heavy air strike to suppress VC fire, the airborne task force landed by choppers at the airstrip on the edge of the camp. After landing it launched an operation designed to drive back the VC and give elbow room to the camp. During this operation the task force uncovered a strong VC fortified position and the fighting became intense. Finally, VC pressure drove the airborne task force back to the airfield. The enemy soon drove so close to the airfield that due to enemy fire once again it became difficult to resupply and evacuate the wounded.
The new enemy force engaged by the airborne task force was discovered to be a NVA regiment. From documents it was learned that this was the same regiment which had overrun Le Thanh District and conducted the subsequent series of ambushes along Highway 19 west of Pleiku in early June. The corps commander realized that he was confronted with a decisive engagement in western Pleiku and that the enemy seemed determined to take Duc Co, the last outpost on Highway 19 between the Cambodian border and Pleiku, the Provincial Capital and headquarters of II Corps. Since the loss of Duc Co would eliminate the last government stronghold in western Pleiku and give the enemy control of Highway 19 from the Cambodian border to the outskirts of Pleiku, the corps commander decided to fight to hold Duc Co. He then began marshalling his reserves for a battle in this key area. The Marine task force was pulled off operations in Kontum and moved rapidly to an assembly area near Pleiku. Additional intelligence of the movement of other VC troops along Highway 19 in the area between Duc Co and the new Le Thanh District headquarters indicated a sizeable VC build-up which would require a reaction force much stronger than was currently available to II Corps. Faced with this enemy build-up, General Vinh Loc again requested additional troops from the General Reserve. Unfortunately, the JGS reserve troops were committed and it was unable to furnish any at this time. The ARVN Joint General Staff then approached General Westmoreland and requested that U.S. forces be moved to Pleiku to allow the ARVN troops garrisoning Pleiku to be utilized to reinforce the Duc Co relief force. General Westmoreland agreed, and the 173d Airborne Brigade moved to Pleiku. Major General Stanley R. Larsen, newly appointed CG of Field Force, Vietnam - a field headquarters formed to command U.S. combat troops in the II Corps area - moved his tactical CP to Pleiku in order to coordinate the use of the 173d with the ARVN corps commander.
Relieved of the responsibility for Pleiku, the corps commander then gathered all available troops and formed another task force consisting of the armored cavalry troop with its tank company and Armored Personnel Carrier company, a ranger battalion and artillery. This armored task force and the Marine task force was given to Sub-Brigadier General Cao Hao Hon, commander of the 24th Special Tactical Zone, who was ordered to relieve the forces beleaguered at Duc Co.
The deployment of the 173d Airborne Brigade to Pleiku, releasing additional ARVN troops for the relief force, upset the VC plans and timetable. The VC are well known for their meticulous gathering of intelligence prior to an operation. They carefully gather data not only on enemy strength to include number of troops, weapons and fortifications, but also the reinforcing capability of the headquarters controlling the zone in which they are in operation. When laying the groundwork for the attack at Duc Co the VC undoubtedly carefully calculated the number of troops garrisoning Duc Co and also estimated the troops available to the Special Zone and II Corps for a relief force. With the arrival of the 173d Brigade, these VC calculations were thrown awry. With these U.S. forces in the Pleiku area as we have noted, the corps commander was able to add additional ARVN forces to the relief force. The result was that VC's carefully calculated ratio of forces and the probability of success at the ambush site changed in favor of the ARVN troops.
On 8 August the relief force under the 24th Special Zone moved out cautiously to the west along Route 19. Prepared for the expected ambush, the troops moved by bounds with infantry elements well off to the side of the road. The first day was uneventful and the column halted early and dug in for the night. They moved out next morning without contact. That afternoon, however, the lead elements ran into a well dug-in and camouflaged position. The lead task force attacked and seized the objective. They suffered a few casualties and lost one tank to a recoiless rifle. Shortly afterward firing came from the south flank and an enemy battalion debouched from a village three kilometers south of Highway 19, driving back the flank security. The enemy troops doubled-timed in extended order in column of companies toward the column attempting to close with the friendly troops before air strikes could be called on them. They continued to assault through the initial air strikes and hit the center of the friendly column cutting it in two.
Air strikes were then concentrated on the portion of the road seized by the NVA battalion and the other NVA units which opened fire from positions surrounding the column. It was now becoming dark, so the two portions of the column reorganized and concentrated on redistributing their troops for that night's defense. During the night the enemy pressed a series of attacks in an attempt to destroy the separated elements of the column, but they were beat off with heavy losses. By the time the sun arose the defensive fires of the relief force, coupled with numerous air strikes during the night, severely punished the enemy troops causing them to finally pull back.
At this time the airborne task force at Duc Co was ordered to attack down Highway 19 to the east to link up with the relief force. Threatened with entrapment between these two attacking forces, the enemy broke contact and withdrew leaving only small delaying forces, snipers and mines along the road. The battle of Duc Co ended with the VC defeated with heavy losses and the government troops in control of the battlefield. The battle of Duc Co raised the morale of the ARVN troops. They had taken the worst the VC could throw at them and had not only held on, but had made the enemy break contact and flee, leaving his weapons and dead on the battlefield. This significant victory was celebrated by visits of General Westmoreland and the principal Vietnamese government officials headed by General Thieu, the Head of State, to the Duc Co camp.
Colonel Theodore Mataxis