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Cambodian Incursion

Operation
Title
Cambodian Incursion
Start Date
4/29/1970
End Date
6/30/1970
CTZ
III
TAO
Cambodia
Objective
relieve pressure on the National Khmer Armed Forces, destroy Communist sanctuaries, capture the headquarters of the Central Office for South Vietnam, demonstrate Vietnamization, buy time for U.S. troops withdrawal, & break the bargaining stalemate
Description
Excursions into Cambodia began in April when RVN forces initiated raids against Communist bases in Parrot's Beak. There were 13 major combat operations in Cambodia during the following months, two of which included U.S. ground units. The other operations were accompanied by U.S. advisors and supported by U.S. air assets. In all, this was the largest series of Allied operations since JUNCTION CITY. There were three groups of operations: TOAN THANG (Total Victory) with ARVN III Corps and U.S. II Field Force; CUU LONG (Mekong) with ARVN IV Coprs; and BINH TAY (Tame the West) with ARVN II Corps and U.S. I Field Force. The ARVN units would reach deeper than 60 kilometers into Cambodia, while the U.S. forces would not push farther than 30 kilometers inside the borders. TOAN THANG 42 was an entirely ARVN operation meant to clear Communist base areas in the Parrot's Beak. During some phases of the operation, the ARVN and National Khmer Armed Forces (FANK) worked together. Eventually they had thwarted the Communist plans to overthrow the Lon Nol regime and captured or killed 3,588. During TOAN THANG 43-46, joint U.S.-ARVN operations worked to clear communist sanctuaries in the Fishhook area. The mission largely became one of search-and-destory when it became obvious that the PAVN would avoid open-battlefield confrontations. The 1st Cavalry stumbled across many supplies during this time, and this part of the Cambodian incursion accounted for 3,190 Communist troops killed or captured. Increased Communist activity forced TOAN THANG 46 to end by 20 June. The ARVN operation CUU LONG I began on 9 May to open the Mekong River. ARVN divisions cleared the banks of the river and repatriated nearly 20,000 Vietnamese in refugee camps. In CUU LONG II, ARVN IV Corps and FANK forces worked together to recapture Takeo and clear Routes 2 and 3. Finally in CUU LONG III, ARVN IV Corps again joined FANK forces to reestablish control over towns and evacuate more ethnic Vietnamese. About this same time, the Allies began to attack bases in Cambodia facing II Corps. These operations were designated BINH TAY I-IV and included ARVN 22d and 23d Infantry divisions, the 2d Ranger Group, the 2d Armor Brigade, and two U.S. 4th Infantry Division brigades. However U.S. participation was brief. The 4th Division ws overextended, and upon attempting to insert into Cambodia, they suffered significant casualties and several downed helicopters. By 16 May, all 4th Division troops had left Cambodia and turned the operation over to the ARVN. In BINH TAY II, ARVN units uncovered more supplies and weapons and in BINH TAY III they searched for Enemy Base Area 740. In BINH TAY IV, ARVN troops pushed back to a FANK garrisonn at Labang Siek and evacuated its 7,000 Khmer soldiers and dependents across the border into Pleiku Province. By 27 June, all II Corps ARVN troops had left. U.S. ground troops left Cambodia by 30 June, but ARVN units continued to operate up to 60 kilometers inside Cambodia all the way into 1971. Throughout the invasion, there were 2,328 Communist soldiers who rallied or were captured. Though the Cambodian incursion captured ten times the supplies captured in Vietnam the previous year, temporarily reduced pressure on Lon Nol, lessened dangers to withdrawing U.S. troops, and displayed ARVN improvement, it was not as succesful as believed. It became obvious that the ARVN depended on U.S. air support and had numerous problems on the tactical and organizational level. This appeared again during the operations in Laos in 1971. The Communists quickly returned to eastern Cambodia and seized more towns in southern Laos while expanding the Ho Chi Minh Trail. As the U.S. continued to withdraw, the ARVN had to deploy troops in III Corps and reduce their strength in the north. The Communist threat grew. Meanwhile in the U.S., the anitwar movement gained a new rallying point. In the end, the Cambodian Invasion turned the war into one for all of Indo-China, which ARVN and FANK troops could not defend on their own.
Allied Units Involved
Unit
50,000 ARVN troops (9th, 21st, 22d, 23d, Divisions)
Unit
30,000 USA troops (3d Brigade, 1st Calvary
Branch
United States Army
Branch Abbrv.
USA
Unit
11th Armored Calvary Regiment
Branch
United States Army
Branch Abbrv.
USA
Unit
4th Infantry Division
Unit
3d ARVN Airborne Brigade)
Killed in Action
638 ARVN ; 338 (USA)
Missing in Action
35
Wounded in Action
4,009 ARVN ; 1,525 (USA)
Enemy Units Involved
Unit
PAVN
Unit
VC
Killed in Action
10,000-11,349+
Sources
Author
Shelby L. Stanton
Title
Vietnam: Order Of Battle
Author
Spencer C. Tucker
Title
The Encyclopedia Of The Vietnam War: A Political, Social & Military History

Vietnam Center & Sam Johnson Vietnam Archive

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