Phase III of the Tet Offensive of 1968 (also known as the August offensive or Third offensive) was launched by the People's Army of Vietnam (PAVN) and Viet Cong (VC) from 17 August to 27 September 1968. The offensive was divided into two waves of attacks from 17 to 31 August 1968 and from 11 to 27 September of that same year.
Background In late June 1968, COSVN and the commanders of Military Region 5 held a series of conferences to review the results of the May offensive, also in attendance was Lê Duẩn who had pushed for the original plan for the General Offensive–General Uprising. The majority of the attendees, including Chinese military advisers, regarded the May offensive as a failure and opposed any renewal of the offensive. Lê Duẩn supported by General Hoàng Văn Thái and General Chu Huy Mân then persuaded the attendees to support the launching of a third offensive by mid-August. The Chinese advisers opposed this decision and returned to China, while several of the Vietnamese who had voiced their opposition to the new offensive were fired. The offensives of May and August were primarily re-directed towards military targets, intending to blunt the perception that military victory was attainable for the United States (US).
On 24 July in Hanoi, Lê Duẩn met with senior leaders responsible for military affairs including PAVN chief of staff, General Văn Tiến Dũng to develop the operational plan for the offensive.
After considering the recommendations submitted by COSVN and Military Region 5, it was agreed that Tây Ninh Province with its proximity to base areas in Cambodia would be the main area of operations. Saigon would not be targeted because of the severe losses suffered by VC forces there in the Tet and May offensives and subsequent Allied security operations. The plan called for the 5th and 9th Divisions to draw the US 25th Infantry Division away from its positions between Tây Ninh and Dầu Tiếng allowing VC local force units to attack Tây Ninh. The 7th Division would attack Lộc Ninh in Bình Long Province to divert the US 1st Infantry Division and the Army of the Republic of Vietnam (ARVN) 5th Division from reinforcing Tây Ninh. Other PAVN/VC units would launch further diversionary attacks across the region.
In the Central Highlands the PAVN 1st Division was to seize the Duc Lap Camp and then move northeast to threaten Buôn Ma Thuột. The PAVN 24th Regiment would cut Highway 14 between Buôn Ma Thuột and Pleiku. The 95C and 101D Regiments would make diversionary attacks on Allied bases across Kon Tum Province, while in the lowland areas VC units would make attacks by fire and sapper attacks on Allied bases.
In central I Corps the PAVN 31st and 38th Regiments would attack the 1st Marine Division positions around Đà Nẵng allowing 6 VC local force battalions to penetrate and attack key installations across the city while the PAVN 368B Artillery Regiment would shell Da Nang Air Base.
In southern I Corps a reinforced regiment from the PAVN 2nd Division would attack Tam Kỳ and another reinforced regiment from the PAVN 3rd Division would attack Quảng Ngãi.
Allied intelligence was able to detect the planning of the offensive, its timing and objectives. On 10 August COMUSMACV General Creighton Abrams reported to the US Joint Chiefs of Staff that the “current deployment of [allied] ground forces is satisfactory,” and he was “confident in our ability” to defeat the offensive. Abrams ordered increased air strikes on suspected PAVN/VC assembly areas, but specifically ordered his commanders not to be drawn out into the countryside, but rather to stay back and defend the population centers.
Offensive
Tây Ninh
On the evening of 17 August a night ambush patrol from Company D, 2nd Battalion, 27th Infantry Regiment, operating between Nui Ba Den and Highway 13 3 km east of Tây Ninh, observed a VC unit marching toward the capital. They called in artillery fire and engaged the VC with small arms and the VC retreated to the north and east.
At midnight on 18 August a battalion from the 273rd Regiment, 9th Division, attacked Firebase Buell II () which was defended by 2 platoons from Company D, 3rd Battalion, 22nd Infantry Regiment, two platoons from Company C, 4th Battalion, 23rd Infantry Regiment and five M48 tanks from Company A, 2nd Battalion, 34th Armor Regiment. The PAVN hit the tanks with B40 Rocket-propelled grenades to no effect and were unable to penetrate the base perimeter. At dawn the PAVN withdrew leaving 104 dead and eight wounded.
At the same time 9th Division sappers climbed Nui Ba Den to attack the US communications station on its summit. The sappers penetrated the perimeter destroying several buildings and the electric generators that provided power to the base. At dawn the PAVN withdrew leaving 15 dead. US losses were eight dead and 23 wounded. New generators were flown in and the base became operational later that day.
Also during the early morning of 18 August the D14 Local Force Battalion and a company from the 275th Regiment attacked southeast Tây Ninh but were held back from the center by Regional and Popular forces and police. At dawn Companies A and B, 4/23rd Infantry moved from Firebase Rawlins III () to southeast Tây Ninh, and the ARVN Task Force 2-34 was deployed to the southwest. Once these blocking forces were in position the Regional and Popular Forces within the city began pushing the PAVN back to the south and by nightfall the D14 Battalion had withdrawn southeast away from the city.
At 09:30 on 18 August, 8 km southeast of Tây Ninh the 275th Regiment ambushed Troop A, 3rd Squadron, 4th Cavalry Regiment on Route 239 in the Cau Khoi Plantation. Company A, 1st Battalion, 5th Infantry Regiment, was dispatched south down Route 26 and attacked the VC flank, killing 34. US casualties totaled four dead and 17 wounded.
At midday on 18 August Company B 1/5th Infantry engaged a two battalion strong PAVN unit in the Bến Củi Rubber Plantation northeast of Tây Ninh. Company C 1/5th Infantry and its reconnaissance platoon were sent to reinforce Company B and with artillery and air support by 16:00 they had scattered the enemy force who left behind 92 dead, a field radio and three .50-caliber machine guns. Captured documents showed that the force comprised a battalion from the 33rd Regiment and the D24 Anti-Aircraft Battalion.
On the morning of 19 August, 1/5th Infantry regained contact with the 33rd Regiment in the Bến Củi Plantation. Companies B and C and the reconnaissance platoon, engaged PAVN who had reoccupied their previous fighting positions. After several M113 armored personnel carriers became bogged down the US advance halted and by dusk the 33rd Regiment withdrew further into the plantation. US losses were two killed and 24 wounded.
At 18:45 on 19 August, the 33rd Regiment ambushed a column of Company B 1/5th Infantry and Troop A 3/4th Cavalry as they moved along Route 239 through the Bến Củi Plantation towards Dầu Tiếng Base Camp. B-40 and recoilless rifle fire knocked out the two leading vehicles and Company B established a defensive position north of the road while artillery and air strikes were called in. At 20:45 a troop from the 3/44th Cavalry attacked the enemy flank allowing the column to disengage and move east, fighting its way through further ambushes with B-40s knocking out two M48s and two M113s. US losses were eight killed and 44 wounded while PAVN losses were estimated to be more than 200.
On the early morning of 20 August, a night ambush platoon from Company A, 2/27th Infantry, 2 km north of Tây Ninh Combat Base spotted a unit of VC. On engaging the unit with their personal weapons, the return fire indicated that they were facing a VC battalion. Air and artillery support was called in while the platoon fought to prevent the VC from overrunning their position. The VC withdrew at dawn leaving 155 dead, US losses were five killed and six wounded.
On the morning of 20 August, Company B, 4/23rd Infantry, was ambushed by elements of the 275th Regiment on Route 26 through the Cau Khoi Plantation. Company A deployed south down Route 26 from Firebase Rawlins III and the combined force made the VC disengage leaving 28 dead. US losses were four dead and seven wounded.
On the morning of 21 August as Company C and the reconnaissance platoon of 1/5th Infantry patrolled the northwest of the Bến Củi Plantation they were engaged by the 33rd Regiment. The PAVN aggressively closed on the US force sending in two battalions of infantry and knocking out the six lead M113s with B-40 rockets. The unit withdrew killing 182 VC for the loss of 18 US killed and 23 wounded. S. Sgt. Marvin R. Young would be posthumously awarded the Medal of Honor for taking command of his platoon after the commander had been killed and covering its withdrawal.
On the afternoon of 21 August Troop A 3/4th Cavalry and Company A 4/23rd Infantry, clashed with VC again in the Cau Khoi Plantation. US losses were three killed and five wounded.
On the night of 21 August the PAVN/VC launched simultaneous attacks on Firebases Buell II and Rawlins III. The 174th Regiment attacked Firebase Buell II which was defended by Companies C and D, 3/22nd Infantry, the attack was repulsed at a cost of 60 PAVN/VC killed and 11 wounded soldiers captured. US losses were 3 killed and 18 wounded. The 3rd Battalion, 275th Regiment attacked Firebase Rawlins III which was defended by Companies A and B, 4/23rd Infantry, the attack was repulsed at a cost of 25 PAVN/VC killed and four wounded soldiers captured. US losses were one killed and ten wounded.
On the morning of 22 August on Route 239 in the Bến Củi Plantation, Company B, 1/5th Infantry, reengaged elements of the 33rd Regiment killing 24 PAVN/VC for the loss of four US dead and 16 wounded.
On 22 August, 25th Infantry Division commander MG Ellis W. Williamson instructed his 2nd Brigade to move north to Dầu Tiếng and on 23 August the 2nd Brigade established its headquarters there and assumed operational control over 1/5th Infantry. Troop A, 3/4th Cavalry, and the 1st and 2nd Battalions, 27th Infantry, each minus one company were also placed under 2nd Brigade operational control. These reinforcements allowed the 1st Brigade to focus its efforts on the areas immediately surrounding Tây Ninh. The 2nd Brigade commander sent a task force comprising Companies A, B and D of the 2/27th Infantry, supported by elements of Troop A, 3/4th Cavalry to construct a new firebase named Schofield () on Route 239 halfway between the Bến Củi and Cau Khoi Plantations. The firebase became operational that evening, with two 105-mm. howitzer units, Battery A, 1st Battalion, 8th Artillery Regiment and Battery C 7th Battalion, 11th Artillery. After midnight on 24 August two battalions from the 33rd Regiment attacked Firebase Schofield in a four hour long assault. PAVN/VC losses were 103 dead and an unusually large number of weapons were captured including four machine guns, four 60-mm. mortar tubes, two recoilless rifles and 11 B-40 launchers. US losses were nine dead and 41 wounded, four M113s and two M48s were destroyed.