SECURITY IN THE PHNOM PENH SPECIAL MILITARY REGION

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CIA-RDP85T00875R001700040030-3
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RIPPUB
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S
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15
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December 20, 2016
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March 30, 2006
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30
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October 1, 1972
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IM
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Approveti.. /F/,- L 1700040fl3O 3 Secret 1#': CIA-RD O 1, DIRECTORATE OF INTELLIGENCE Secret ER IM 72-147 October 1972 Copy No. 79 Approved For Release 2006/04/19 : CIA-RDP85T00875R001700040030-3 Intelligence Memorandum Security in the Phnom Penh Special Military Region 25X1 Approved For Release 2006/04/19 : CIA-RDP85T00875R001700040030-3 Approved For Release 2006/04/19 : CIA-RDP85T00875R001700040030-3 Approved For Release 2006/04/19 - A-R P8 T00875R001700040030-3 SVC CENTRAL INTELLIGENCE AGENCY Directorate of Intelligence October 1972 INTELLIGENCE MEMORANDUM SECURITY IN THE PHNOM PENH SPECIAL MILITARY REGION I. The Phnom Penh Special Military Region (PPSMR) consists of Kandal Province and several appendages encompassing significant towns and installat;ons (see Figure 1). It contains the seats of both governmental and military authority, most of the country's commercial activity, and about one- third of the nation's population. Moreover, all major road, rail, and water transport systems channel through Phnom Penh. Because this concentration is crucial to the national life of Cambodia, its defense has assumed very great importance in strategic planning. This memorandum assesses Forces Armees Nationales Khmeres (FANK) defenses within the PPSMR. Defense of the PPSMRJi 2. To defend Phnom Penh, Cambodia maintains a total ground force strength in the PPSMR normally averaging 50,000 to 60,000 men - about 25% to 30% of FANK's total. The backbone of the defense of Phnom Penh, however, is a combat force of about 20,000 troops deployed in a loose arc extending up to 40 kilometers from the capital. Roughly half of this strength - organized into four brigades and one regiment - is composed o; Territorial Forces directly subordinate to administrative authorities within the PPSMR. The other half - three brigade groupsJfrom the General Reserve - 1. For a discussion of the organization of the PPSM R, see the Appendix. 2. A brigade group usually consists of two brigades. Note: This memorandum was prepared by the Office of Economic Research and coordinated within the Directorate of Intelligence. Approved For Release 2006/04/fiEe R W 85T00875R001700040030-3 Approved For Release 2006/04/19 : CIA-RDP85T00875R001700040030-3 SECRET Phnom Penh Special Military Region T~ C.1 '01 Kendal province boundary Area appended to PPSMR 62 Operational sector Approved For Release 2006/04/SEq'P85T00875R001700040030-3 Approved For Release 2006/04/19 : CIA-RDP85T00875R001700040030-3 SECRET are operationally attached to the military region in a defensive role. In this capacity, however, they remain available for deployment elsewhere if needed. Generally, the Territorial Force units are deployed to the north and south, while the General Reserve units are in more sensitive positions to the west along Route 4 and to the east in the Vihear Suor marshes (see Figure 2). 3. These forces can be rapidly reinforced by airborne elements, with a strength of about 3,500, normally stationed near Pochentong Airport, and by two mobile armored personnel carrier units, with a total of about 400 men. In addition, the bulk of Cambodia's combat support units, about 10,000 troops, and some 24,000 headquarters personnel are quartered in and around the capital, although they would be only marginally effective in a combat role. Because Phnom Penh stands at the hub of i.he Cambodian transportation system, its defenses can be further augmented by drawing mobile General Reserve units from other parts of the country, assuming no interdiction. For example, when elements of the Communists' Phuoc Long Front threatened the area west of the city in late 1971, FANK strength quickly increased by 10,000 to 20,000 men. 4. In the city itself, major installations such as Pochentong Airport have separate defensive perimeters and provide their own security forces (Pochentong, for example, has three Air Force security battalions), while security for other vital installations - bridges, generating facilities, etc. - is provided by Prevote Militaire (Military Police) and infantry units. The Prevote Militaire also man checkpoints on all roads leading into the city and operate patrols in the urban area. A small local reinforcement capability is available for deployment to trouble spots, but a lack of adequate communications hampers its effective use. 5. Artillery for the capital area is concentrated in eleven fire support bases (FSBs) containing twenty-eight 105-nom howitzers and one 75-men howitzer - the largest such concentration in .he country. The FSB system provides the environs of Phnom Penh with a fairly comprehensive artillery umbrella, although it has some gapsJ(see Figure 3). In addition, some of the crews remain only marginally trained, and there is a general lack of forward observers to adjust fire. Despite these handicaps, however, counter-battery fire in reaction to enemy initiatives has shown steady improvement and is now frequently immediate and accurate. Further support is provided by nightly surveillance flights by AC-47 gunships and T-28 sorties flown from Pochentong Airport in response to emergencies. Naval fire 7upport, staged from the base at Chrui Chang War, has been effective, although seldom used. 3. While most areas z an be covered by at least two FSBs, there are gaps. Security is generally satisfactory, but supporting infantry may not always be available. Thus the enemy could negate part of the capital's artillery umbrella by overrunning or e or more isolated FSBs. Those to the north are especially vulnerable. Approved For Release 2006/04/19Fa Q$ 85T00875R001700040030-3 Approved For Release 2006/04/I9s f fPj 5TOO875RO01700040030-3 PANK Units Committed to Defense of PPSMR th Territorial Force General Reserve (SubJect to deployment elsewhere) Brigade Regiment er Miles Kllo+m o' tars 4 Approved For Release 2006/04/' 6X85T00875R001700040030-3 Approved For Release 2006/04/1 85T00875ROO1700040030-3 Artillery Coverage of the PPSMR Figure 3 Approved For Release 2006/04/1 &R85T00875R001700040030-3 Approved For Release 2006/04/19 : CIA-RDP85T00875R001700040030-3 SECRET 6. Although the Cambodians have partly implemented their plans to enhance the security of Phnom Penh, there have been significant shortfalls in the program. For example, the FANK units deployed around the outskirts of Phnom Penh have been content to remain in defensive positions, many of which do not contain adequate cover. Furthermore, the organization and construction of an inner defense belt consisting of a dike reinforced by bunkers, under development since early 1971, is still only about 10%complete. Moreover, a "rocket belt" for the city and Pochentong Airport to preclude 122- mm rocket attacks has not yet been established. The Mekong River 7. The Mekong River, which traverses the FPSMR from north to south, has been Phnom Penh's main supply route for more then a year. Because of its importance, an autonomous Mekong Special Zonewas created in January 1971 to coordinate the defense of convoys plying the 100-kilometer corridor from the border with Vietnam to Phnom Penh. 8. The Zone has an assigned strength of about 2,000 troops deployed in a series of some 50 positions of platoon to company size and 11 FSBs (see Figure 3). Two General Reserve brigades also operate in the area but are subject to deployment elsewhere. The FSBs are equipped with twenty-two 75- mm and two 105-mm howitzers which provide comprehensive coverage of the river and its banks from the South Vietnamese border to the vicinity of Phnom Penh. This FANK contingent occasionally is supplemented by Ranger elements of the South Vietnamese armed forces which operate south of Neak Luong. 9. The convoys which run from Tan Chau, South Vietnam, to Phnom Penh about every 10 to 15 days usually consist of five to ten merchant ships and an assortment of tug-drawn barges. Escorts for the convoy are provided by both the Cambodian and South Vietnamese navies. Between the South Vietnamese border and Neak Luong, about half of the journey, the escort force is mixed; while beyond Neak Luong the escort is solely Cambodian because of the greater security of the area and political sensitivities. Even south of Neak Luong, however, the Cambodian navy provides most of the escort force - about 40 vessels, including a small waterborne assault force. 10. The concept of security for the Mekong is primarily reactive. Units stationed on the banks normally remain in defensive positions, with the exception of the periods during which convoys are on the river. Even then, patrolling is shallow and has not prevented the enemy from gaining temporary acce~- ':o the banks of the rive. Naval and air support, on the other hand, has been excellent. Naval elements, have been willing to move against enemy positions and return fire while landing reaction forces, and attacks by orbiting gunships have been effective in quickly suppressing enemy fire. 4. See the Appendix for details. Approved For Release 2006/04/19 : MT00875R001700040030-3 Approved For Release 2006/04/19 : 9k ff ff 00875R001700040030-3 11. The watershed of the Bassac River, lying in the southwestern part of the PPSMR, is not encompassed by the Mekong "corridor" or the Phnom Penh "perimeter." The Bassac Basin is only lightly defended by a scattered handful of company and platoon-size positions. Infrequent FANK sweeps c,;cur, but are temporary and do little to establish friendly control. Naval and artillery support are not normally available for this area. FANK's de facto resignation from the Bassac area has given the Communists ample opportunity to build a civil administration and recruit for military units and has provided the enemy a secure base area close to the border and Phnom Penh alike. Enemy Commitment in the PPSMR 12, The Communists have shown little inclination to seize control of FANK.-held areas of the PPSMR, contenting themselves with civil administration of the lightly defended Bassac Basin. They have, however, maintained an occasionally heavy level of harassing fire, terrorism, and sapper attacks against Phnom Penh and, on several occasions, have deployed large units into close proximity to the capital. This recurring threat has repeatedly caused FANK to terminate or diminish operations elsewhere in order to pull units into Phnom Penh's defensive perimeter. 13. Prior to the 1972 offensive, VC/NVA combat strength in and near the PPSMR was estimated to be 6,000 to 7,000, representing the bulk of the Comn;um.st commitment there. This force consisted of elements of as many as five regiments - the 96th and 211th Artillery Regiments east of Phnom Penh, as well as two regiments of the Phuoc Long Font and the possible 367th Sapper Group to the west and north. A smaller Khmer Communist (KC) force was composed of at least two battalion-size entities and a number of smaller units. 14. This Communist force has been significantly reduced by commitments to the current Vietnamese Communist offensive in South Vietnam. The two regiments of the Phuoc Long Front have moved to the border area southwest of Phnom Penh, while the 96th Artillery Regiment has deployed into South Vietnam, leaving a residual force of 3,000 to 4,000 VC/NVA; K.C troops in the PPSMR. Of those remaining, the 367th Sapper Group appears to be targeted against the city of Phnom Penh, while the 211th Artillery Regiment, previously tasked with disrupting traffic on the Mekong, may still have this mission. There have been some indications that the 211th Regiment may have been disbanded, but even if this is the case, it is possible that some of the components of the unit are st ill operating in the PPS M R area. 15. The Communists also have a fairly active fifth column in the PPSMR. Both the KC and VC have agents, recruiters, proselytizers, and administrative personnel in Phnom Penh. Little is known about the KC Approved For Release 2006/04/19 : 6rA(R'MTT00875R001700040030-3 Approved For Release 2006/04/19 : CIA-RDP85T00875R001700040030-3 SECRET apparatus, although reports indicate that it occasionally infiltrates sapper elements into the city for specific missions. The VC are known to be relatively self-sustaining, maintaining only occasional liaison with the KC and receiving only a nominal amount of support from Vietnamese Communist entities outside the city. Effective Communist civil administrative structures have not been reported in Phnom Penh or its immediate vicinity but are well established in the Bassac Basin where FANK presence is minimal. Barring a substantial pacification effort, the Bassac Basin could develop into a major Communist civil/ military base area in close proximity to the capital. 16. Logistically, the PPSMR is not crucial to the Communists. A major north-south supply line runs through the eastern fringe along the Tonle i och River, but heavy annual flooding, the natural barrier of the Mekong, and the sheer pre;ence of large numbers of FANK troops have deterred the use of supply lines running across the PPSMR from east to west. Nonetheless, the Communists do procure illegally substantial quantities of supplies such as food and medicine - although they are not known to have procured ordnance - in the Phnom Pen'.i area. Combat Act.vity 17. Almost all of the fighting that has occurred in the PPSMR has Leen enemy initiated, as FAN K has taken little actionJto pre-empt the Communists' capability to attack or harass their positions. Despite this lack of FANK initiative, the Communists have concentrated on low-cost harassment and interdiction, suggesting tiiat they are relatively content with the status quo in the PPSMR. 18. Only in two instances has the enemy undertaken major action in the PPSMR. The first, and most se -ious, occurred in May-June 1971, when three regiments under the operational control of the VC 9th Division deployed to within 20 kilometers of Phnom Penh with the mission of securing the Tonle Toch corridor for increased supply movements to South Vietnam. Several small FANK garrisons along the river were attacked and isolated, but elements of FANK's 7th Brigade broke through stiff enemy resistance to relieve them after three weeks of heavy fighting and turned back the enemy attack. 19. In October 1971 the Communists again moved a large force into the Phnom Penh area, this time primarily to divert FANK from Operation CHENLA II in Kompong Thom Province. Shortly after VC 9th Division elements moved against the CHENLA 11 column, several regiments of the Phuoc Long Front deployed from the hills west of Angtassom in Military Region II to the flatlands west of Phnom Penh. This diversion was successful, 5. Short-term, small-unit clearing operations were initiated in the spring of 1972 as part of Operation FUNAN, but have accomplished little. Approved For Release 2006/04/1 SE4 85T00875R001700040030-3 Approved For Release 2006/04/19 : CIA-RDP85T00875R001700040030-3 SECRET forcing FANK to counter by withdrawing several brigades from the CHENLA -area, as well as several more from other parts of the country, to strengthen the capital's defenses. FANK attempts to dislodge the enemy were ineffective, however, and the enemy maintained the threat for several weeks until finally withdrawing voluntarily after the collapse of CHENLA II. 20. To date, the city of Phnom Penh itself has not been subjected to large-scale ground attacks. However, the enemy has taken advantage of porous FANK defenses to infiltrate small units into outlying areas, where they have executed spectacular, but not usuall?' militarily significant, sapper attacks and attacks by fire. Other groups ofr even smaller size have committed occasional acts of terrorism in the heart of the city. Combat incidents have averaged about 40 per month within 20 kilometers of Phnom Penh, ranging from 7 in September 1972 to 84 during the height of the Phuoc Long Front threat. 21. The enemy's most successful attack on the city was the January 1971 sapper raid on Pochentong..Airport in which a unit of about 100 men was able to destroy a large portion of Cambodia's modest air force. Fifty-one military aircraft were destroyed, 17 were damaged, a large store of ammunition was lost, and several buildings - including the main terminal - were damaged. Another round of coordinated attacks on several installations was launched under the cover of a massive rocket barrage in late March 1972. Although several aircraft were destroyed, FANK defenders drove off a sizable (possibly battalion-size) sapper group attempting to reach the Route 1 bridge over the Bassac River in Phnom Penh's southeastern quadrant'. In the Latest attack on the city in early October 1972, a battalion-size enemy force captured six armored personnel carriers from a FANK unitcaught olfguard in the northern part of town. Using the vehicles, the Communists attempted to push further into the city but were stopped by FANK security elements, who killed more than 80 of the enemy. The Communists were successful, however, in blowing up three spans of the Chrui Chang War bridge which connects the capitol with the Northeast. 22. The enemy has also been able t j move small artillery units sufficiently close to the city to execute occasional short-term, spectacular attacks by fire using recoilless rifles and B-40/122-mm rockets. Most of the standoff attacks have come from the north and west; despite relatively accurate fire, they have not caused any large-scale destruction of military facilities. 23. Terrorist incidents in Phnom Penh have not been too damaging '.,r frequent. A rough pattern has developed, however, which suggests that the enemy consciously increases terrorism in response to large- scale military activity in other parts of the country. For example, two peak Approved For Release 2006/04/19: STUOR)EWTOO875 R001700040030-3 Approved For Release 2006/04/19 : CIA-RDP85T00875R001700040030-3 SECRET months of terrorist actions in 1971 - September and November - roughly corresponded, respectively, with the start of CHENLA II and the growing threat from the Phuoc Long Front. Likewise, an upsurge occurred in the spring of 1972, simultaneously with the movement of enemy units to the border area for the spring offensive. Many of the terrorist attacks have appeared to be non- selective - usually occurring at public gatherings such as theaters and restaurants - but at least one attempt was made to assassinate the First Minister in August 1972. Several attacks against US personnel have also occurred, including a September 1972 attempt on tl:c life of the charge d'affaires. Attacks on Mekong Shipping 24. The cnemy has only sporadically subjected merchant shipping on the Mekong to harassment since a series of attacks in early 1971 led to the initiating of the convoy system. Attacks have been generally ineffectual for a number of reasons, foremost among which are the limited enemy commitment and effective friendly reaction. Rocket and mortar fire (high angle) has proved 'ineffective against moving targets on the river, and the enemy has not yet been willing to move heavy weapons close enough to the banks to employ them in a direct fire mode. In the instances in which weapons as large as 75-mm recoilless rifles have been used, they have caused only light damage to the ships, and the fire has been quickly suppressed by naval and gunship counter-battery fire. Capabilities and Prospects 25. Security in the PPSMR is fragile and probably will remain so barring a marked improvement in FANK leadership. FANK's defenses have developed only slowly despite the overriding importance of the region. An adequate extended perimeter to prevent attacks by fire on the capital has not been developed, and the units committed to its defenses are tied to fixed positions. Lax internal security has failed to guard against terrorism and sabotage, and the capital is still vulnerable to sapper, raids, attacks by fire, and ground probes. Defenses on the Mekong River are spread thin, and FANK presence in the Bassac Basin is almost non-existent. Thus the e;uemy capability to harass the capital, the Mekong, and other supply lines seems likely to continue virtually unabated for the foreseeable future. Communist initiatives are likely to be geared to maintaining sufficient pressure on FANK to permit continued growth of the KC, as well as utilization of supply lines and base areas near the PPSMR. The situation in the Bassac Basin represents perhaps the most significant threat to the security of the capital. The Cambodians have generally ignored the development of the KC infrastructure and Communist Approved For Release 2006/04/19 : 5T00875RO01700040030-3 Approved For Release 2006/04/19 : CIA-RDP85T00875R001700040030-3 SECRET military activity in the area, despite its proximity to Phnom Penh. Barring successful pacification efforts, the Basin - with its large Vietnamese population - could become the setting for the development of a major concentration of enemy strength within easy striking range of the capital. 26. On balance, weighing existing FANK defenses and current enemy capabilities, FANK can probably maintain control of the capital. ~vr;, should the North Vietnamese alter their priorities and commit a force of two or more divisions against Phnom Penh by redeploying units no, , targeted against South Vietnam, FANK probably would require both extensive air support and South Vietnamese assistance to hold the city. Moreover, in the absence of positive FANK actions against the expanding KC military structure, the KC may in the future be capable of seriously threatening the capital without direct assistance from the Vietnamese Communists. Approved For Release 2006/04/19SC185T00875R001700040030-3 Approved For Release 2006/04/19 : CIA-RDP85T00875R001700040030-3 SECRET Organization of the PPSMR and the Mekong Special Zone The Phnom Penh Special Military Region (PPSMR) was organized shortly after the coup in 1970 to consolidate the capital's defense under one unified command. For the most part, the PPSMR iscotirminous with Kandal Province, although some limited areas have been appended either to extend the operational boundaries outward from Phnom Penh or to envelope sensitive areas. Prior to the coup, Kandal Province was administered as part of Military Region 1, with the exception of Phnom Penh, which was designated General Headquarters. In the frantic shuffling thatfollowed the change in government, the province was first shifted to the control of Military Region II and later designated the PPSMR. In July 1970 a buffer zone a round Oudong and Lovek was appended (Area A on Figure 1) to enhance the security of the ordnance depot and other installations in the area. Then, in October 1970, parts of Kompong Speu and Takeo Provi.:!:;i~s were annexed, both to push the boundaries outward from Phnom Penh and encompass the important towns of Tram Khnar and Chambak (Area B on Figure 1). More recently, as the Mekong has evolved as thrt capital's lifeline, additional territory on the east bank of the Mekong was annexed (Area C on Figure 1). In early July 1971, Lon No] reportedly approved in principle a plan to redesignate the PPSMR as Military Region VI, but the plan was never formally executed. Another part of the plan involving the formation of six operational sectors (Secteurs Operationnels - SO) within the Military Region, however, has been implemented. The sectors, headquarters, and areas of responsibility are as follows: S061 - Phnom Penh, city of Phnom Penh S062 - Oudong (VU 7307), north of Phnom Penh S063 - Vihear Suor (WT 0691), east of Phnom Penh SO64 - Takhmau (VT 9870), south of Phnom Penh S065 - l:antout (VT 8064), southwest of Phnom Penh S066 - Near Pochentong Airport, west-northwest of Phnom Penh The Mekong Special Zone which is directly subordinate to the General Staff (thus making it autonomous from the PPSMR) was established on 8 January 1971. It was created to counter growing enemy activity against river shipping by placing all FANK operations involving the Mekong under one command. The boundaries are defined by a series of three small rivers on the east side of the Mekong for the first 55 kilometers north of the border, after which the boundary follows a line approximately 4 kilometers from the Mekong to Phnom Penh.The western boundary is a line 4 kilometers from the river between the border and Phnom Penh. Approved For Release 2006/04/PgGG~ -DOD85TOO875