As they debated whether the Army or Navy would control the river flotillas, French Vice Admiral Philippe Auboyneau proposed for the first time the organisation of a Vietnamese Marine Corps.

On October 13, 1954, Prime Minister Ngo Dinh Diem signed a government decree formally creating within the naval establishment a section of infantry, then of brigade strength, later to be designated as the Marine Corps (VNMC).

[16]: 460–1 After midnight on 20 September during the Phase III Offensive, the VC 1st Battalion, 272nd Regiment, attacked a Regional Forces outpost in Phước Tân hamlet, 20 km west of Tay Ninh City, losing 35 killed in the brief assault.

[18]: 39 During Operation Lam Son 719 on 21 March 1971 the Marines at Fire Support Base Delta, south of Route 9 in Laos, came under intense ground and artillery attacks.

[21]: 27 By 11:00 on 2 April the ARVN 20th Tank Battalion moved forward to Đông Hà to support the 258th Marine Brigade in and around the town and defend the crucial road and rail bridges across the Cua Viet River.

[22]: 50–2  Marine ANGLICO units called in naval gunfire to hit PAVN forces near the bridges on the north bank of the river and destroyed 4 PT-76 amphibious tanks east of Đông Hà.

[21]: 30  The capture of Camp Carroll and Mai Loc allowed PAVN forces to cross the Cam Lộ bridge, 11 km to the west of Đông Hà.

On 7 April the Marines withdrew from Đông Hà leaving the defense to the 57th Regiment, the 1st ARVN Armored Brigade, 20th Tank Battalion and the 4th and 5th Ranger Groups.

[23]: 211–3 On 11 July, following preparatory B-52 strikes, the 1st Marine Battalion was deployed by HMM-164 and HMM-165 helicopters to two landing zones 2 km northeast of the city to cut Route 560, the main PAVN supply line.

The helicopter landing proceeded smoothly, while the ground assault met heavy resistance and could only break through PAVN defenses with air and artillery support.

[22]: 123–6  Meanwhile, between 11 and 15 September the 2nd Marine Battalion advanced to the southern bank of the Thạch Hãn River, where they halted, exhausted and depleted by heavy casualties and unable to push on to Đông Hà.

[22]: 126 In late October 1972 the ARVN and Marines began attacks north of Quảng Trị to try to regain positions along the south bank of the Cam Lộ/Cửa Việt River.

[22]: 134  Besides ARVN firepower, twelve B-52 bombers from the US Air Force and naval gunfire of the United States Seventh Fleet was used to soften the PAVN-occupied Cửa Việt Base and hinder PAVN reinforcements.

[22]: 135  On the evening of 29 January, the PAVN launched a counterattack against Task Force Tango, and by the next day had succeeded in cutting off its lines of communication and began bombarding the encircled Marines.

[26]: 155 On 12 March, I Corps commander General Trưởng received the JGS order to pull the Airborne Division out of the line and start it moving to Saigon.

Trưởng immediately called General Viên to protest the decision but learned that President Thieu had personally directed the deployment so that the Airborne Division could participate in the offensive to retake Ban Me Thuot.

Trưởng and Thi anticipated a mass civilian exodus from Quảng Trị as soon as the people saw that the Marines were leaving, and he directed his staff to prepare plans to assist the refugees.

[26]: 157 On 18 March, Khiêm flew to Da Nang to meet with Trưởng and advised him that due to attacks elsewhere no additional troops would be sent to I Corps; the promised 468th Marine Brigade would remain in the defense of Saigon.

[26]: 158 On 19 March at meetings in Saigon with Thiệu Trưởng was directed to stop the evacuation of Hue and to defend enclaves at Huế, Da Nang, Chu Lai and Quang Ngai City.

The Imperial City would be defended despite the fact that PAVN artillery had, on 19 March, already struck inside the Citadel and Highway 1 was clogged with the southbound traffic of thousands of refugees.

[26]: 158–9 On the morning of 21 March the lead battalions of the PAVN 324B and 325th Divisions, together with the independent Tri-Thien Regiment, with heavy artillery support, assaulted South Vietnamese positions from the Bo Corridor to Phú Lộc.

Other formations of the 325th, notably the 101st Regiment, forced the 60th Ranger Battalion, 15th Group, from Hill 500 west of Phú Lộc, and supporting artillery interdicted Highway 1.

[26]: 159 On 23 March the 913th Regional Forces Group on the My Chanh Line north of Huế withdrew without orders and they refused to stop at the next delaying position near Phong Dien District Town.

By the time these orders were issued, what was left of the population of Hue was streaming toward Tân Mỹ Base to take any available boat or ship out of Thua Thien Province.

The 51st Infantry pulled back and located just west of the city while the division headquarters and the 1st Regiment, which had suffered moderate casualties in the Nui Bong sector, were around Huế.

Trưởng flew over the column making its way down the long stretch of Vinh Loc Island and noted that the only apparent disciplined, cohesive units were marines.

Also on 26 March, the marine battalion of the 258th Brigade holding the Phu Gia Pass, a short, twisting defile about 15 km east of Phú Lộc District Town came under attack.

With the PAVN approaching the Hải Vân Pass from the north and Vietnamese Navy boats breaking down faster than they could be repaired, Trưởng stopped the sea movement of forces and equipment from Huế.

Brigadier general Trần Quang Khôi, commander of the 3rd Armored was given responsibility for defending Bien Hoa, although PAVN shelling had rendered the base unusable.

[27]: 488–90  The 3rd Armored was moving from Bien Hoa to attack PAVN forces when they heard the surrender broadcast of President Dương Văn Minh and Khôi halted his advance and disbanded the unit.