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After Action Report 59
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AVFBC                                             31 July 1970

SUBJECT:    II FFORCEV Commander's Evaluation Report - Cambodian Operations (U)

United States Military Assistance Command, Vietnam
APO  96222

1.     (C)     INTRODUCTION:

     a.     This report provides a summary of the “Cambodian Campaign” conducted by HQ, II FFORCEV, in conjunction with HQ, III Corps, during the period 29 April to 30 June 1970.

     b.     Operational Area:

     (1)     The area of operation extended from the Parrot's Beak, vicinity of the III and IV Military Region * boundaries (XS3194), north along the Cambodian-RVN frontier, to the boundary between III and II Military Regions (YU4160).

     (2)     III corps operations were conducted initially in the Angel's Wing (BA706) - Parrot's Beak (BA367) area and were later expanded to the west in the vicinity of Phnom Penh (VT7890), and to the northwest near Kompang Cham (WU5126).

     (3)     US operations were targeted against enemy base areas along the northwestern and northern tier of the Corps from Base Area 354 (WT9775), south of the Dog's head, to the vicinity of O Rang (YU34464).

     (4)     Sketch map at Appendix 12 to Annex A graphically portrays US and GVN operational areas.


*Military Region - formerly Corps Tactical Zone.

SUBJECT:  II FFORCEV Commander's Evaluation Report - Cambodian
             Operations (U)

     c.     The abrupt change in the political posture of the Cambodian Government, stemming from the removal of Prince Sihanouk as Head of State, and the announced plans of the new government to eliminate the Communist/NVA presence in Cambodia established the framework that permitted the GVN to conduct operations against enemy base areas which had long provided the enemy with a safe haven from which to launch offensive operations and to resupply his forces in the III Military Region.

     d.     In early March, the enemy gave every indication that he was being hard pressed to accomplish his basic objectives within III Military Region despite the recent withdrawal of the1st Infantry Division from the Corps area.  US forces were disposed throughout the Military Region participating in Dong Tien* programs, upgrading territorial forces and conducting ground combat operations against enemy local and main force units primarily in the interior of the corps.  Only minimal forces were deployed in the border areas.

     e.     At the time directives to initiate planning for operations in Cambodia were received, US and GVN forces were deploying in an effort to isolate and destroy the remaining enemy force elements and eliminate his infrastructure.  US/GVN units had to be re-oriented, task organizations realigned and units displaced over considerable distances during a short period of intense preparations.  The successful repositioning of major maneuver forces and control elements was facilitated by the improved combat capability of territorial forces to control key areas, with nominal assistance by regular ARVN reaction forces.

     f.     During the period 14-17 April, CG, III Corps, conducted a highly successful operation against enemy sanctuaries in the Angel's Wing in Cambodia.#  A second operation of major proportion was initiated in the force of cavalry, infantry, and rangers.


*Dong Tien (Progress Together ) - Program of close association of designated RVNAF forces with designated US/FWMAF forces on a continuing basis in specific areas.
#Operation Toan Thang 41

SUBJECT:    II FFORCEV Commander's Evaluation Report - Cambodian Operations (U)

     g.      In late March a staff representative discussed the feasibility of US and GVN combat operations in Cambodia at MACV headquarters.  Two general areas were selected as the proposed operational objective areas:  the Angel's Wing - Parrot's Beak Area of Cambodia (Base Areas 367 and 706) and the Fishhook (Base Area 352).  Initial thinking visualized an operation of 14 to 30 days duration, with the possibility of staying longer in the event developments warranted further exploitation.  A concept was proposed for forces from the 1st Cavalry Division (AM), ARVN Abn Division, and the 11th Armored Cavalry Regiment to enter the Fishhook and elements of III Corps' newly formed mobile task forces to operate against the Angel's Wing - Parrot's Beak Area.  25th Infantry Division forces were proposed for operations in this latter area as an alternative plan.

     h.     On 24 April, CG, II FFORCEV, received instructions to be prepared to conduct military operations in Cambodia against base areas in the Fishhook.  The attack in Cambodia was proposed to be launched within 72 hours following the decision.  This was later shortened to 48 hours after permission was received to extend the planning down to brigade level.  The original date for initiation of operations was 30 April.  By direction from Washington, the attack was delayed 24 hours and US forces crossed the border on 1 May.

     i.     CG, III Corps, completed plans on 27 April to conduct operations in the Angel's Wind - Parrot's Beak area.  This coordinated operation, Toan Thang 42, involved forces from III and IV Military Regions and commenced on 29 April.

     j.     The main objective of the US attack into Cambodia was to be the destruction of enemy facilities and the capture or destruction of enemy material.  Additional enemy base areas were selected for attack:  350, north of Loc Ninh; 351, north of Bu Dop; 354, west of Trai Bi; and 707, north of Thien Ngon.

     k.     With the commitment of major forces to cross-boarder operations, force levels in the interior of the Corps Zone were considerably reduced.  An economy of force concept was adopted with heavy reliance placed on territorial forces for security.  The weakened condition of enemy forces throughout the III Military Region and the disruption of the enemy's command and control apparatus by the Cambodian operations contributed to his inability to mount significant attacks or threaten pacification.

     l.     The close hold nature of the initial plan for operations in Cambodia had the advantage of reducing the risk of compromise but at the same time precluded advanced coordination.  Detailed plans were releasable only to key staff officers in the early stages of planning.  Consequently, the execution phase initially required extensive, continuing command attention and coordination.
SUBJECT:    II FFORCEV Commander's Evaluation Report - Cambodian Operations (U)

     m.     On 6 June, CC, II FFORCEV,      issued planning guidance for accomplishment of withdrawal of US forces from Cambodia.  This planning guidance provided for a transition phase into a posture desired for US forces in accordance with the newly promulgated wet season strategy.  The withdrawal was successfully completed in accordance with the plan by 291800 June 1970.  A special feature of withdrawal planning was the integrated air cavalry, artillery and tactical air offensive against enemy units and storage areas in the Fishhook.  Air cavalry operations were launched on 25 June in coordination with planned and on-call tac air strikes and artillery concentrations against known and acquired enemy targets.  Additionally, four to six B-52 strikes were flown daily in support of this destruction campaign.

2.     (C)     INTELLIGENCE:

     a.     The enemy level of activity was low to moderate during the months preceding allied operations in Cambodia, with enemy forces within the corps area concentrating their efforts on countering pacification and the enemy divisions on the corps border engaging in sporadic attacks by fire against allied FSBs.  F1 April marked a high point in enemy activity in the interior of the corps area as the enemy initiated phase one of Campaign “X”.  During the night of 31 March - 1 April, there were 56 enemy initiated ground incidents reported, including ground probes and several heavy attacks by fire.  This high point was followed during the month by other attacks by fire on allied installations and an increase in terrorist incidents in Saigon and other areas.

     b.     Prior to allied operations in Cambodia, three enemy divisions were deployed around the northern and northwestern border of the corps area.  Early in April, the 9th VC Div moved south into an area that extended from the Dog's Neck to the Angel's Wing, and included the western portion of Tay Ninh (P).  The apparent mission of the division was to conduct attacks against ARVN and US forces operating near the border.  It appeared also that some elements of the division were targeted against Cambodian units to the west of the Angel's Wing.  With the shift of the 9th VC Div, the 7th NVA Div moved from its old area in northern Binh Long and Phuoc Long Provinces westward to the Fishhook area, presumably to take over the mission of the 9th VC Div.  This westward shift of the 7th NVA Div and the 9th VC Div increased the area of operation of the 5th VC Div which then extended from the Binh Long/Phuoc Long boundary to the II Corps border.  The mission of the division was to provide security for the 86th Rear Service Group and its base area long the Cambodian border, and to attack allied installations in Phuoc Long.

SUBJECT:    II FFORCEV Commander's Evaluation Report - Cambodian Operations (U)

     c.     Immediately prior to cross-border operations, enemy activity in III Military Region increased as phase one of Campaign “X” was initiated.  Campaign “X” was the enemy's primary task for 1970, and was a revitalized effort to achieve the goals of COSVN Resolution 9.  This resolution emphasized psychological rather than military victories through attempts to discredit GVN control and pacification efforts, and cause increased political pressures for a US withdrawal from the war.  The campaign was intended to create a significant change in the war, hopefully with violent and uninterrupted attacks as extensive and intense as those of the 1968 TET Offensive.  A further discussion of the enemy situation in Cambodia to include an analysis of weather and terrain is contained in Annex B (Intelligence).

3.     (C)     MISSION:  The mission assigned to US and GVN forces for the Cambodian Campaign was as follows:  II FFORCEV, in conjunction with III Corps, conducts offensive operations in Cambodia to destroy VC/NVA installations and destroy an/or capture enemy equipment and supplies in Base Areas 350, 351, 352, 353, 354, 367, 706, and 707 and adjacent areas; continue current operations and programs in remainder of III Military Region with available forces.

4.     (C)     EXECUTION:

     a.     A resume of US and GVN combat operations conducted in Cambodia during the period 29 April through 30 June is included at Annex A.  To provide a more complete understanding of the evaluation, Annex A should be read after completion of the basic report.

     b.     Annexes C through N provide a narrative summary of support provided by supporting forces and the various general staff sections.

     c.     Statistical results of each operation are outlined in Annexes O through S with a total US/GVN results tabulation at Annex T.

     d.     Command and Control:

     (1)     Liaison Teams.  To insure timely processing of information, II FFORCEV established a liaison team with each major control headquarters:  1st Cavalry Division, 25th Infantry Division, and HQ, III Corps Forward.  Additionally, during the early stages of joint operations between III and IV Corps. US liaison was established at HQ, IV Corps.  Liaison teams within III Corps were provided dedicated VHF and secure voice radio communication direct to the II FFORCEV TOC.  A liaison officer from this HQ was also stationed at HQ, MACV.

SUBJECT:    II FFORCEV Commander's Evaluation Report - Cambodian Operations (U)

     (2)     Reporting of Information.  Special reports were established to standardize and expedite processing of operational information.  Two reports were required daily as of 08-and 1600 hrs with a weekly wrap-up for each border operation submitted every Saturday.  Units reporting were: 1st Cavalry Division, 25th Infantry Div, DSA, III Corps; Senior Advisor, ARVN Airborne Division; and Senior Advisor, 5th ARVN Division.  Information reported included changes in task organization, number of GVN and US troops in Cambodia and RVN, narrative summary of the day's combat activity, statistical results for the period, cumulative totals for the operation, US support provided to RVNAF (tactical air, artillery, resupply, medical evacuation, and vehicle recovery), plans for the next 24-hours, and material denied the enemy.

     (3)     II FFORCEV Tactical Operations Center.  To accommodate the heavy influx of data, additional officers were assigned as TOC desk officers for each of the reporting headquarters.  These officers were responsible for processing spot reports, collating input data, preparing ledger sheets of operational results, reviewing future plans summaries, and assisting in preparation of the MACV operations summary report.

     (4)     Combat Actions in Specific Areas.  II FFORCEV rules of engagement authorized an operational area to a maximum depth of 30 kilometers into Cambodia.  Within this area, three zones were established for the conduct of specified combat activity.

     (a)     Area of Operation (AO) was the area assigned by CG, II FFORCEV, in which commanders would conduct the full range of combat operations.  The amount of area allocated was varied to focus the efforts of the divisions in the border base areas.  As area search progressed, AO's were expanded to provide for search of additional areas.

     (b)     Combat Reconnaissance Zone was the area adjacent to the AO in which commanders were authorized to employ air cavalry and observed or planned fires.  However, division commanders were required to request permission to employ ground forces within this zone.

     (c)     Visual Reconnaissance Zone was the area extending beyond the Combat Reconnaissance Zone to the 30 kilometer limit.  This area was intended primarily for early warning and for the conduct of visual reconnaissance and surveillance.  This zone was designated to assure sufficient reaction to enemy activity.  Late in the campaign, commanders were permitted to employ forces in this one, subject to prior notification and approval of CG, II FFORCEV.  (see Appendix 13 to Annex A)

     (5)     Support of GVN Operations in Cambodia.

SUBJECT:    II FFORCEV Commander's Evaluation Report - Cambodian Operations (U)

     (a)     US advisory support was provided to ARVN units while they remained within the 30 kilometer limit.  As their forces penetrated beyond this distance, US advisors were withdrawn.

     (b)     US Army aircraft operating in the III Corps Cambodian AO were not permitted to cross the 30 kilometer limit, unless approved by CG, II FFORCEV, for cases of emergency.  There were no cases in which this authority was required to be exercised and at no time did US Army aircraft exceed the 30 kilometer limit.  With the exception of those aircraft committed to direct support missions of III Corps operations, all aircraft entering the III Corps AO were required to obtain permission form DSA, III corps prior to crossing the Cambodian/RVN border.

     (c)     US artillery and engineer units committed to support of GVN Cambodian operations were restricted to operations within the 30 kilometer limit.  Impact zones of artillery and other weapons systems were required to be within the 30 kilometer area.


     a.     Vietnamese operations.  General Tri's operations into the Angel's Wing and Parrot's Beak area on 29 April 1970, came as no surprise to the enemy, insofar as anticipation of the attach was concerned.  However, the enemy was taken by surprise by the depth and rapidity of the ARVN thrust and its sustained momentum.  These operations demonstrated that ARVN commanders possess the professional skills and leadership qualities required to conduct aggressive combat independently.  Their tactics were generally sound; however, problems developed in combined arms coordination, employment of mechanized and armored forces, use of supporting artillery and other fire support mean, and first and second echelon maintenance.  More effective use of resources was noted as the combined arms teams gained combat experience.  US advisors contributed significantly to increased effectiveness of ARVN tactical units, although it should be noted that ARVN units operated successfully beyond the 30 kilometer limit.

     b.     US Operations:

     (1)     Commitment of US forces into Cambodia was a complete tactical surprise to the enemy.  There was no initial resistance and US aircraft were able to move freely over the battlefield.  It was not until about 14 May that the enemy was capable of demonstrating a semblance of organized resistance.  However, strategic surprise was not achieved.  Following the overthrow of Sihanouk, the enemy had acted to safeguard his base areas and supplies.  As a consequence, an estimated 400-600 tons of supplies, mostly small arms and B-40 Rocket ammunition were removed from the border area.

SUBJECT:    II FFORCEV Commander's Evaluation Report - Cambodian Operations (U)

     (2)     The enemy's strength in rear service areas had been grossly under-estimated.  It had been thought that in the continuous base areas opposite III Military Region, the enemy had approximately 27,000 headquarters, administrative, and logistical personnel.  Conservative estimates, based on captured documents, now reveal that the rear area strength was as high as 63,000.

     (3)     Additionally, US forces were not prepared for the difficulty experienced in locating enemy storage areas.  Most cache sites were artfully hidden in underground bunkers, deep in triple canopy jungle.  There was no pattern to the location of depots and service activities.  Some storage sites were adjacent to high speed roads while others were situated in isolated jungle areas, accessible only by foot or bicycle paths.  Many finds were made by using electronic/magnetic aids such as mine sweepers and probes.  Also used effectively was a Navy-developed magnetic anomaly detector.  This device was helicopter mounted and could detect small metal objects at an altitude of 250 feet.  Approximately 10% of its sensings turned out to be caches.

     c.     Overall Assessment:

     (1)     There has been considerable discussion about whether US operations in Cambodia provoked the Communists into wider operations of their own in that country.  In May the Communists, through their propaganda, attempted to create the illusion that their activities in Cambodia were caused by our cross-border operations.  Intelligence reports revealed that in late March and early April the VC/NVA initiated planning for operations to assert control in much larger areas of Cambodia, if not to induce the actual overthrow of the Lon Nol government.  Prior to 1 May, elements of the 5th and 9th VC Divisions had already moved from their traditional base areas to new locations from which to threaten Cambodian population centers.

     (2)     An assessment of the overall results of US and Vietnamese operations must be categorized into three principal areas.

     (a)     Quantitative evaluation.  The vast amounts of weapons and tonnages of rice and ammunition may be totaled and compared to the number of enemy regiments or battalions that could be sustained.  This, however, does not relate the true significance of the damage done to the enemy.  The value of this impact must be measured in terms of the amount of resources, personnel, money and energy required to replace the material and equipment lost.  Accordingly, as the enemy attempts to reconstruct this logistical foundation, there will be an operational pause of some degree in III Military Region.  Deprived of resupply, those VC/NVA forces deployed in III MR will have difficulty sustaining an effective insurgency for the next 4 or 5 months.

SUBJECT:    II FFORCEV Commander's Evaluation Report - Cambodian Operations (U)

     (b)     Command and Control.  The enemy command and control system has been placed under severe strain, his communications-liaison routes have been disrupted, and his base areas pre-empted.  To regain tactical direction and control, he must relocate travel routes for resupply and infiltration and rebuild his base storage areas.  Additionally, hospitals must be reestablished, headquarters installations constructed, and rest and training areas rebuilt.  To accomplish these tasks while prosecuting operational objectives in Cambodia will require a concentration of resources and personnel that he probably cannot afford.

     (c)     Psychological assessment.  The Allied cross-border campaign created a psychological turmoil within the enemy's organizational structure.  The number of Hoi Chanhs substantially increased.  Increasingly large numbers of political cadre rallied, some of high positions such as the deputy commander of SR-2 and various staff section chiefs at the VC sub-region and province level.  There are reports that some NVA soldiers refused to fight and were sent to rear service units.  Some tactical units avoided contact or lacked aggressiveness.

     (3)     The psychological effects of these cross-border operations impacted on the GVN at the highest levels, and on the RVNAF, the territorial forces and the people at the hamlet level.  It is too soon for a complete evaluation, but significant consequences at all levels within Vietnam can be expected.  The most immediate impact will probably occur among the people of hamlets located in the border provinces.

     (4)     Although the performance of ARVN was by no means of uniform excellence during the campaign, there was clear evidence of favorable progress.  Regional and popular forces had to assume crucial responsibility for security of the people during the absence of a high percentage of US and ARVN maneuver forces.  While these forces were not completely tested during this period, for the most part they reacted above expectations.

     d.     Outlook.  A set of conditions has been created now that should not have been viewed as probably on 1 April.  The major aim at this point is to take advantage of the opportunity to assure the success of the Vietnamization Program and guarantee the withdrawal of US forces in accordance with the President's timetable.  US and GVN forces have gained an advantage over the enemy for the moment which must be thoroughly and aggressively exploited.

                    /s/ George K. Webb
                    GEORGE K. WEBB
                    Colonel, GS
                    Acting Chief of Staff
SUBJECT:    II FFORCEV Commander's Evaluation Report - Cambodian
               Operations (U)