SECURITY IN THE PHNOM PENH SPECIAL MILITARY REGION

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP85T00875R001700040030-3
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 15
• Document Creation Date: December 20, 2016
• Document Release Date: March 30, 2006
• Sequence Number: 30
• Publication Date: October 1, 1972
• Content Type: IM

 Approveti.. /F/,-
L
1700040fl3O 3
Secret
1#': CIA-RD O 1,
DIRECTORATE OF
INTELLIGENCE
Secret
ER IM 72-147
October 1972
Copy No.
79
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Intelligence Memorandum
Security in the Phnom Penh Special Military Region
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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.
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Phnom Penh Special Military Region
T~ C.1 '01
Kendal province boundary
Area appended to PPSMR
62 Operational sector
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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.
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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
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Artillery Coverage of the PPSMR Figure 3
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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.
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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
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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.
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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
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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
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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.
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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.
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