Phase Two of the Tet Offensive of 1968 (also known as the May Offensive, Little Tet, and Mini-Tet) was launched by the People's Army of Vietnam (PAVN) and Viet Cong (VC) against targets throughout South Vietnam, including Saigon from 29 April to 30 May 1968. The May Offensive was comparable in bloodshed to the initial phase of the Tet Offensive. The United States (US) had 2,169 men killed by hostile action in the month of May, making it the deadliest month of the entire Vietnam War for US forces, but South Vietnamese losses were 3,467, significantly less than the 5,025 killed in February during the original Tet Offensive. The US claim that PAVN/VC losses exceeded 24,000 killed and over 2,000 captured. The May Offensive was a costly defeat for the PAVN/VC.
Background
In late March 1968, COSVN and B2 Front leaders held meetings to review the results of the Tet Offensive. Lê Duẩn, the driving force behind the Tet Offensive, and General Hoàng Văn Thái wished to renew the offensive before the start of the southern monsoon began in mid-May in order to improve their position at the Paris Peace Talks which were about to commence. Some field commanders opposed any renewed offensive citing the heavy losses suffered by the VC and resulting poor morale, the inexperience of replacement PAVN troops and logistics problems, while Allied post-Tet operations Truong Cong Dinh and Quyet Thang meant that "there was no longer any opportunity to liberate the cities and province capitals" with a Tet-style offensive. COSVN leaders ignored these objections believing that the element of surprise meant they still had the advantage over Allied forces and recommended to the Politburo that the offensive should be renewed. After consulting with the other fronts in South Vietnam, the Politburo instructed the PAVN high command to begin planning the new offensive. Part of the offensive was meant to "bring the war to the enemy's own lair", meaning to shift the battlefield from the countryside to significant urban attacks, with the resulting damage inflicted upon urban centres. The targets of the attack was more limited than the Tet Offensive, but still primarily aimed at attacks throughout Saigon and major urban centres.
Unlike the original Tet Offensive which sought to seize nearly every major city in South Vietnam in the hope of provoking a general uprising among the population, the new offensive only involved an assault on Saigon with other towns and cities being harassed by mortars, rockets and artillery fire. Approximately 60,000 PAVN/VC soldiers would take part in the offensive including 30 PAVN infantry regiments, four artillery regiments, three composite PAVN/VC infantry regiments and ten VC provincial infantry battalions. The major targets would be Saigon in III Corps and Đông Hà near the Demilitarized Zone (DMZ) in I Corps. Regimental-strength operations were planned in Quảng Tín of I Corps, Kon Tum and Bình Định of II Corps.
On 19 April, the PAVN chief political officer of Sub-Region 1, Lieutenant colonel Tran Van Dac, surrendered to South Vietnamese forces in Bình Dương Province. Dac revealed that the PAVN/VC planned to attack Saigon and other targets across the country at the end of April. After two days of questioning, US and South Vietnamese intelligence concluded that Dac was telling the truth and his information and other signals and human intelligence led COMUSMACV General William Westmoreland to advise his senior commanders that another offensive was imminent and instruct them to move forces back to defend Saigon. News of Dac's defection leaked within days and the Politburo decided to proceed with the offensive given that Dac's knowledge was limited to the planned attacks on Saigon, but to delay the start of the offensive by one week, other than around the DMZ, in the hope that the Allies would think the Saigon attack had been cancelled and lower their guard.
Offensive
DMZ
On 29 April, the PAVN 320th Division attacked An Binh, north of Đông Hà Combat Base, this drew two Battalions of the Army of the Republic of Vietnam (ARVN) 2nd Regiment into a running battle and the 1st Battalion 9th Marines was sent in to support the ARVN resulting in a seven-hour long battle that left 11 Marines, 17 ARVN and over 150 PAVN dead. The following day the 3rd Battalion 9th Marines arrived to support the Marine/ARVN force and was ambushed north of Cam Vu, 20 Marines and 41 PAVN were killed. Also on 30 April, a PAVN unit opened fire on a US Navy Clearwater patrol from entrenched positions near Dai Do, 2.5 km northeast of Đông Hà. It was later discovered that four PAVN Battalions including two from the 48th and 52nd Regiments of the 320th Division had established themselves at Dai Do. The Battle of Dai Do lasted until 3 May and resulted in 81 Marines and over 600 PAVN killed. The PAVN engaged US and ARVN forces elsewhere around Đông Hà from 4–6 May, on the evening of 6 May the 2nd Brigade 1st Cavalry Division was deployed into Tru Kinh to conduct Operation Concordia Square and on 9 May was ambushed by a PAVN force resulting in 16 US dead for the loss of 80 PAVN. On 10 May a night attack north of Nhi Ha was broken up by air, artillery and naval support, 159 PAVN were killed. After this the 320th had broken into small groups and was moving back towards the DMZ, from 9–17 May the 2nd Brigade reported killing 349 PAVN for the loss of 28 killed.
While it seemed that the 320th had abandoned their attempts to take Đông Hà, this was just a temporary lull. On 22 May a unit from the 320th ran into a Company from 3rd Battalion 3rd Marines between Con Thien and Gio Linh and was caught in the open by Marine artillery and air support. East of Con Thien the 1st Battalion 4th Marines encountered another PAVN unit setting off a two-day battle as the PAVN tried to escape back through the DMZ resulting in 23 Marines and 225 PAVN killed. On 25 May in actions at Dai Do and Nhi Ha 350 PAVN were killed. In two actions at Tru Kinh on 26 May over 56 PAVN were killed for the loss of ten Marines, while the ARVN killed 110 PAVN north of Thuong Nghia. On 27 May the Marines killed 28 PAVN and by 30 May the 320th was attempting to escape through the Marine and ARVN cordon. Total PAVN losses in the second Battle of Đông Hà were over 1,000 killed.
Saigon
First wave
At 04:00 on 5 May, a VC unit attacked ARVN positions at the Newport Bridge and simultaneously VC wearing Marine uniforms attacked Marine positions closer to the city centre. At 04:30 a battalion sized VC force was engaged near the Phú Thọ Racetrack where heavy fighting had taken place during the Tet Offensive. At 10:00 the ARVN Airborne was engaged by VC north of Tan Son Nhut Air Base. Two battalions of the VC 271st Regiment followed by another regiment, attacked eastward in the ARVN 5th Ranger Group's Cholon sector. Using small arms, automatic weapons, and rocket fire, they attempted to seize the headquarters of the 6th Police Precinct. Throughout the morning, the 30th Ranger Battalion was heavily engaged with forces of the 3rd Battalion, 271st Regiment, less than 3 km due west of the Phú Thọ Racetrack. Although the Rangers had managed to slow the VC with artillery and helicopter assistance, the fight was still raging in the early afternoon. UH-1 Huey helicopter gunships of the 120th Aviation Company Gunship Platoon at Tan Son Nhut AB were called in to support the Rangers and they hit the VC positions, one gunship was hit by VC fire and crash-landed and burnt on the ground while the crew escaped unharmed.
On 6 May, the 3rd Squadron, 4th Cavalry Regiment was engaged by a VC force near the village of Ap Hoa Thanh on the western edge of Saigon. The ARVN 30th and 33rd Ranger Battalions joined with US Cavalry forces to attack a hamlet west of Phú Thọ Racetrack, meeting heavy resistance they withdrew and called in air and artillery strikes, on entering the hamlet the next morning they counted over 200 VC dead. A unit from the 199th Light Infantry Brigade was engaged by VC forces in a hamlet west of Saigon starting a three-day running battle, after multiple air and artillery strikes the US force overran the village, finding concrete-reinforced bunkers which had only been destroyed by delayed-fuze 750 lb bombs.
On 7 May, the 35th Ranger Battalion, who had established a cordon with the National Police north of Cholon, were ordered to attack VC positions to the north. They were met by heavy fire including B-40 rockets described by their US adviser as "coming in like hail". The Rangers withdrew to allow airstrikes against the VC and assaulted again but were again stopped by heavy fire. On 8 May the 38th Ranger Battalion relieved the 35th Rangers and attempted to restart the advance but made little progress until aided by US Cavalry forces. The assault slowly continued on 9 May finding 45 VC dead.
From 7–12 May in the Battle of South Saigon, units of the US 9th Infantry Division fought off four VC battalions as they tried to attack the city from the south killing 200-250 VC.
On 10 May, the 33rd Rangers swept the area around Phú Thọ Racetrack finding 9 VC dead and various weapons and supplies.
On 11 May, the 38th Rangers continued advancing to the north supported by airstrikes. The VC began to disengage across Saigon and the attack was largely over. The 3/4 Cavalry withdrew from the area and its area of operations was taken over by the Rangers.
At 02:45 on 12 May, VC sappers attacked the Newport Bridge, detonating explosive charges on two of the bridge piers causing a 100-foot (30 m) section of the north lane to drop into the river below, the VC withdrew by 04:00. The 33rd Rangers continued their sweeps around Phú Thọ finding a further 100 VC dead.
VC losses in and around Saigon between 5 and 13 May amounted to 3,058 dead and 221 captured. ARVN losses were 90 dead and 16 missing, while US losses were 76 dead and one missing.
VC/PAVN forces evacuating east from Saigon engaged the 1st Australian Task Force in the Battle of Coral–Balmoral from 12 May to 6 June.
Second wave
The second phase began on the night of 24–25 May when the K3 and K4 Battalions of the Dong Nai Regiment and the K1 and K2 Battalions from the 1st Quyet Thang Regiment entered Gia Định City, a northern suburb sandwiched between Gò Vấp District and downtown Saigon. Even though the four battalions had only 80-100 men apiece, they had orders to attack the town’s large police headquarters, seize a pair of bridges that led into downtown Saigon, and then take over the city’s radio and television stations. The VC had hardly set foot in Gia Định City when they were assailed by the South Vietnamese 1st and 6th Marine Battalions. The 436th Regional Forces Company and National Police joined the hunt, while the ARVN 1st, 5th and 11th Airborne Battalions sealed off the edges of the suburb. The VC lost at least 40 killed on the first day, including the regimental commander and the senior political officer of 1st Quyet Thang Regiment. The list of VC troops killed or captured grew in the coming days. Among those taken prisoner were the executive officer of the K3 Battalion and the political officer of the K4 Battalion, who provided valuable intelligence about the VC’s plans. By 1 June, the four battalions had been reduced to just 70 healthy soldiers and 30 wounded men who could still fight.
The western thrust against Saigon began on the night of 26–27 May. The 273rd Regiment headed toward Phu Lam alongside the 6th Binh Tan and 308th Battalions, the latter unit having just arrived from the delta. The Vietnamese 2nd Marine Battalion bore the brunt of the initial assault. The 2nd Battalion, 273rd Regiment, attacked the 4th Battalion, 23rd Infantry Regiment, which was camped some six kilometers west of Saigon. The VC broke contact after 90 minutes, but the battalion caught up with them at daybreak. Reinforced by Troops A and C of the 3rd Squadron, 4th Cavalry Regiment, the Americans nearly annihilated the 2nd Battalion, killing 243 VC while losing six killed and 28 wounded. As the fighting increased around Phu Lam, the ARVN 38th Ranger Battalion, minus one company, and the reconnaissance company from the ARVN 5th Ranger Group rushed in to help the South Vietnamese marines. Aided by gunships, the two battalions took 23 prisoners and killed around 370 VC over the next four days. Nevertheless, the VC showed great determination, and approximately 200 troops, mostly from the 6th Binh Tan Battalion, managed to slip past the allied screen into Cholon.