THE DETECTION OF INFILTRATION AND SUPPLY MOVEMENTS INTO SOUTH VIETNAM IN A POST-HOSTILITIES ENVIRONMENT

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80R01720R000700110005-4
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 12
• Document Creation Date: December 16, 2016
• Document Release Date: June 28, 2005
• Sequence Number: 5
• Publication Date: October 30, 1972
• Content Type: MEMO

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The Detection of Infiltration and Suppiv movements Into
South Vietnam in a Post-Hostilities Environment
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Introduction
1. The successful detection of North Vietnamese
infiltration of men and supplies into South Vietnam in
a post-hostilities environment controlled by some form
of settlement agreement would require a large and
comprehensive surveillance program. This memorandum
discusses, in summary fashion, the principal measures
which would have to be included in such a program. The
program outlined to detect. movements into South Vietnam
would apply to southern Laos as well. An Annex extends
the requirements for monitoring North Vietnamese movements
of manpower and supplies into northern Laos. This
memorandum does not, however, consider the question of
Communist supply movements within Laos or Cambodia or the
movement of stocks from Communist caches in these countries
into South Vietnam.
2. It is our judgment that no inspection organization
of feasible size can expect to do even a minimally
effective job if it is limited in its geographical location
to the territory of South Vietnam alone. Furthermore,
the South Vietnamese land border with Cambodia and Laos
is so long and provides so many crossing points that the
only useful approach -- and it is the one which this
memorandum takes -- is to exercise the inspection and
control. function at the borders of North Vietnam itself.
3. Even the task of monitoring supply and personnel
movements along the North Vietnamese border will be
extremely difficult. North Vietnam has a very complex
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logistic system, even though i t is primitive by U.S .
standards. In the following discussion we describe a
program hi.ch ,,,would have a reasonable chance of detecting
large movements of personnel or materiel. It must be
emphasized that if E=e North Vietna_-ioese are determined to
engaged: in small-scale surreptitious infiltration over a
prolonged period, it is doubtful that any practicable
surveillance system could prevent them from doing so.*
Pattern of North Vietnamese Supply and Personnel.
Infiltration
4. North Vietnam has historically used a number of
different resupply and infiltration routes. Movement from
the Hanoi area into southern North Vietnam is primarily by
rail as far south as Vinh. There,'supplies and personnel
are transferred to vehicles for movement into South Vietnam-
or southern Laos. Upon reaching the terminus of their
rail journey at Vinh, supplies and men can be moved by a
myriad of routes which have burgeoned throughout- southern
Indochina during the course of the war. Traditionally, for
example, personnel infiltration to South Vietnam has been
via routes through the Ban Karai Pass into the Laos
Panhandle. Other corridors could as easily accommodate
this flow, of course, and in recent weeks there has been
evidence that the Communists are adding to their traditional
manpower infiltration system a number of new. routes west
of the DMZ. Thee logistic resupply -routes make use of four
major corridors from North Vietnam into southern Laos, and
most recently, numerous direct routes across the DMZ.
This labyrinthine system of roads is supplemented by a
petroleum pipeline system extending the length of North
Vietnam and on into northern South Vietnam and South Laos;
its existence considerably lessens the resupply burden
placed on rail and truck routes.
5. North Vietnamese supply and manpower movements
have usually been closely related to seasonal weather
patterns in Southeast Asia. Though the monsoons affect
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di it ,rent areas at different times, thei r prime impact
over the years has been during the June through September
period when rains peak in the Laos Panhandle, and both
large-scale resupply and personnel infiltration to Ca .'odia.
and the lover half of South Vie tna;mt ceases or is reduced
to a trickle. Typically, by late September personnel
infiltration through southern Laos begins to pick up, while
the marked increase in logistical activity lags by a least
a month until major supply routes have cried out and are
ready to carry heavy vehicle loads.
The Desirability of Inspection within North Vietnam
6. At the present time, the infiltration of supplies
or personnel to the south generally commences in or around
Hanoi, and via rail (under a non-bombing environment)
moves on to Vinh. Vinh is a marshalling center for the major
part of all infiltration and supply movements -- either
into Laos or directly into South Vietnam. Thus, Vinh appears
a logical first point for detecting the covert movement of
war materiel and troops. If a number of inspection teams
were stationed in and around Vinh on the railway and the
several. highways entering and leaving the city, we would
be in a fairly good position to detect the. beginnings of
a large-scale surreptitious buildup in the south at its
inception. The greatest difficulty of such surveillance
would be that supplies and personnel ilovi nl through the Vinh
area could be not only destined for covert buildup in South
Vietnam but could also be destined for NVA units operating
in North Vietnam nearer the DMZ. (A buildup of NVA strength
in this area, of course, would also be a threat to South
Vietnam, though-such a buildup would probably not. contravene
the proposed peace agreement.)
7. If inspection teams were also placed on the major
north-south roads to the west of Vinh, the chances of
properly identifying a military buildup directed at South
Vietnam would be considerably enhanced. However, any
concept of establishing an east-west line across the whole
of North Vietnam near Vinh, with inspection teams all the
way along the line, is impractical. It would require
impossibly large numbers of inspection personnel.
monitoring of Exit Routes Out of North Vietnam
8. In addition to inspection teams at Vinh, an even
partially effective approach to monitoring the southward
movement of man and materiel would require surveillance of
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the logistics channels which lead either directly or
indirectly from North Vietnam into South Vietnam.-;: T1 e
direct routes include the major roads and the POL pipeline
which run across the D ~iZ . The indirect routes incl.uda
tit roads, river, and POL pipelines from North Vietnam to
southern Laos and the sea routes from North to South
Vietnam.
9. in general, inspection teams should be placed on
all major roads where they exit North Vietnam.. As for
the POL pipelines, supply movements across international
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teams. To cover possible covert movement by other than
these major routes, we recommend aerial surveillance of
the North Vietnam border and coast
h
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border. Specific details are as follows:
10. First, the direct routes across the DMZ;
Optimally, an inspection team should be emplaced just
to the north of the DMZ on every road which leads into the
DMZ. The major roads are shown on the map attached to
this memorandum. To monitor movements across the DNIZ would
require inspection of traffic on Routes 103, 120, 102, 1006,
1000, 1022, and 1A. In addition, to prevent the possible
covert construction of new roads or motorable trails into
the DMZ, periodic, albeit irregularly scheduled, close
ground inspections of the northern boundary of the DMZ
would be needed. Finally, the DPP1Z is bisected by the Ben
Hai River. A series of surveillance posts placed along
that river (every few miles over its 40-mile boundary
length), supplemented by river patrols, would reduce the
chance for surreptitious activity across the DMZ.
11. The indirect routes leading from North to South
.Vietnam via Laos should have similar inspection teams at
every major border crossing. The terrain along the Laos-
North Vietnam border makes its crossing difficult, and
routes have been built through virtually all the passes
* In the discussion which follows, we have identified
inspection locations on the North Vietnamese side of the
border. Such placement would be ideal in that border
roads, once they leave North Vietnam, generally divide
into several branches. If inspection were to be instituted
on the Laos and South Vietnamese side of the border, more
stations would be required.
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where the terrain makes construction feasible.* Specliical-ly,
inspection teams would be needed at a poi.nt or po?_n fts on
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of N~~..1 a re Pass, S;.
R.o~.lte 3 just eas~i. _ o~. the ip r:ilarly, north of
the iu Gia and Ban Karai Passes inspection teams Quid be
required on Routes l' and 137, respectively. ','lest of the
DMZ, a number of roach have been constructed during the
past two years. Inspection teams ,,7ould be required on
Routes 910, 1.039, and 1032 and on the adjacent Se Bang
Hieng River. Finally, frequent close inspection would be
required at all the pass areas to determine if additional
routes were being constructed.
25X1 12. The POL pipeline \utilized by the North Vietnamese
should be relatively easy to monitorl
I supervising the flow of petroleum across
nternati.onal borders to Laos and South Vietnam?.
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three lines from soutl'ern North Vietnam: one amn--c"my
across the DMZ to South Vietnam and one each through Mu
Gia Pass and west of the DMZ to Laos. Other available
intelligence sources, such as aerial photography (if they
remain viable under the cease-fire terms), should detect
any construction of new POL pipelines.
13. Once the above measures were implemented, and;
further improvement in our ability to monitor the covert
infiltration of men and supplies would recc.lire the use of
technical surveillance. most important would be a
continuation of aerial surveillance along North Vietnam's
international borders, including both lo,q-flying aerial
observers to monitor border activity visually and
photography" of the border area to allow closer inspection.
Optimally, this coverage should be over all of the major
logistics/infiltration corridors out of North Vietnam, on
the North Vietnam side of the border, in the DMZ and on the
western side of the Laos-North Vietnam border. It should
be carried out on a frequent but irregular basis both
durin the day and at nicrht.
on the main routes.
* All of the pass routes from North Vietnam into Laos,
how,eever, have some bypasses adjacent to the main route, and
it is possible for more such bypasses to be constructed.
Inspection teams would be. needed on each bypass as well as
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detecting movements just outside North Vietnam which had'
gone undetected inside that count.rv.
Se,a Infil trai..ion
7_ In addition to the Ho Chi M,Il inh 'fail t rougC, Laos
and the roads, across the D?MMZ, North Vietnams has in the Past
attempted to use Steel-nulled trawlersr to provide support
for its forces in South Vietnam. Although the enemy's
sea infiltration program has been small and relatively
unsuccessful compared to their overland resupply efforts,
it could play an important part in a covert resupply
campaign. Since 1969, there have been at least 50 sea
infiltration attempts, only three of which are known to
have been successful. About 800 of the known attempts
were destined for GVN PAIR-4 in the Delta, including the
three successes (all of which occurred during the period
August 1970-March 1971). The importance of seaborne
infiltration to the enemy has been attested to this past
dry season. Eighteen trawlers were detected attempting
to smuggle supplies to GVN MR-4 (all of -these -attempts
were unsuccessful) .
The Market Time Surveillance System
15. North. Vietnamese trawlers have departed for South
Vietnam both from the port of Haiphong and from sin Using
Harbor on China's Hainan Island. The U.S. and GVM; have
relied on extensive air and sea surveillance off both the
North Vietnamese and South Vietnamese coasts to detect
the trawlers enroute. The outermost barrier (50 to over
200 miles) has been maintained by the P-3 aircraft operating
under U.S. Navy control. This air barrier has been
extremely effective in detecting enemy trawlers and is
the mainstay of the present Market Time operation; almost
all the trawlers detected by Market Time forces since
August 1969 have been initially sighted by P-3 crews.
once a trawler has been sighted, an effort is made to
maintain continuous visual and radar contact with the
trawler, and the crew of the trawler normally becomes
aware of the surveillance in short order.
16. Since July 1972, the South Vietnamese navy has
assumed responsibility for command and control of all surface
surveillance operations off the coast of South Vietnam.
itiorttn Vietnam's inventory of steel-hulled trawlers consists
of about 50 SL Class trawlers with ca pacitie.`s ranging from
100 -to 400 metric tons each.
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Control of the coastal surveillance organization is no:qexe-,q_
t.sed through four coastal zone conimanders. Each of
these authorities has as his deputy the commander of the
coastal flotilla assigned to his area.
Future Requ re_m.ents
17. To detect sea infiltration during an in- place cease-
fire, the following steps are recomu??ended:
-- The tiarket Time outer barrier should be retained,
using P-3 aircraft. To be most effective, these
flights should occur on a daily basis.
-- The coastal surveillance system should he
maintained and operated on a 24-hour basis.
-- Observers should be placed in the port of Haiphon-
to monitor the departure of trawlers.
The first two recommendations are essential if' effective
monitoring is to take place. The latter, while useful,
would not be essential and could be given up in the
bargaining process. (tie believe it to be unnecessary --
and not feasible -- to set up teams for ground visual
surveillance along the coast of South Vie-nam because of
the sheer magnitude of the effort that would be required.)
18. While the steps enumerated above should be
effective in detecting sea infiltration attempts, it ~. rould
be difficult to "?prove" any cease-fire violations. In
the past, infiltration trawlers which have become aware of
airborne surveillance usually have aborted their mission
while still in international water and returned to port.
Thus, unless a trawler entered South Vietnamese territorial
waters, it could not be seized and inspected, and
violations would be almost impossible to prove.
19. One other maritime infiltration possibility exists;
namely, the Communists could try to move supplies (and
manpower) into northern South Vietnam on small fishing
boats with 'a 5- to 10-ton capacity. These boats, which are
not able to operate on the high seas, could move along the
coast and offload supplies. To prevent this, some type of
coastal. patrol would have to be maintained near the D7,1Z
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with the power to board and inspect suspect ships. r ven
with extensive patron i ncr, L?o: e :'er , sI all-scale ^o+loi` erit
probably could cake place.
A Special Note on Personnel In.-Filtration
20. The North Vietnamese personnel infiltration corridor
begins in the city of Vinh in Nghe An Province, North
Vietnam, and moves along the road network through Ha Tinh
and. Quang Binh Provinces to the Laotian border and the DMZ.
In recent years the two roads most often associated with
personnel infiltration inside North Vietnam are Route 1A,
which runs along the coast from. Vinh to the DMZ, and
Route 137, which runs from Route 1A -through the Ban Karai
Pass into the Laotian Panhandle. As indicated earlier, this
area of North Vietnam, especially around the main marshalling
point of Vinh, would be one useful location from which to
monitor possible preparations for personnel infiltration
in violation of the cease-fire agreements. It is in this
area that significant numbers of personnel would be
concentrated the longest, and it is the area t,ihere
inspection teams would most likely detect personnel
movements.
21. Once the infiltrators leave North Vietnam., they
follow a diverse road and trail system -- both through
Laos and across the DMZ. In Laos and northern South
Vietnam, the personnel infiltration corridor is a maze of
narrow footpaths and trails usually not more than 1-1/2 to
3 feet wide. These trails parallel the major road networks
used for the transportation of supplies but may be separated
from such roads by several miles distance. Many of the
trails pass through dense vegetation that limits lateral
visibility to 20 feet or less and are under thick jungle
canopy, which make observations from the air all but
impossible.
the best means to detect illegal personnel infiltration in
the future may be a combination of inspection teams at
Vinh and extensive foot-patrolling across the trail
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net+ o r i from as far west as Nuong Phi ne in Lao3 east through
Tchepone and then along Route 9 through northern South
Vietnam to the coast. Even with such measLl._es, D.ie should
nob b sanguine about our chances of detecting _"'.lore than a
portion of covert infiltrat on. The prospects for ground
patrols observing infiltration as it occurs is not great,
dough. -it might be possible to dam:, tect areas where
infiltrators have already passed. The greater the number
of patrols, obviously the greater the chance of detection.
Aerial observation
not likely to be effective in detecting personnel
infiltration in these areas.
Here again, extremely active foot-patrolling by inspection
teams would provide the best chance of finding such stations.
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A!dNEX
1. Communist military activity -in north Laos is
supported almost entirely by supplies provided from
external sources via North Vietnam. Three r,-major route
systems are presently used, but others could become
important if the North Vietnamese undertook to design a
logistic system to support a covert buildup.
2. The primary area of interest in north Laos is the
Plaine des Jarres (PDJ) region. Activity there is primarily
supplied by the Route 7 corridor which leads from the Phu
Dien Chau area of North Vietnam (north of Vinh) into
north Laos and the PDJ. Just east of the Laos-North Vietnam
border, Nuong Sen is the focal point for infiltration
toward the PDJ. Thus, our objective should be to place
inspection teams in the NuongSen area and on all possible
bypass roads over which the Communists could move supplies
through that area.
3. Several potential routes to the PDJ region come from
the south and. west, but they are unlike!,,,, candidates for
covert resupply routes. Route 811 extends north from the
Nape Pass area toward the PDJ, but this route terminates
well to the southeast of the PDJ area, and its use would
require large-scale portering of supplies.
4. Sam Neua is the second major area of interest in
north Laos. Numerous routes cross the North Vietnam-Laos
border into the Sam Neua area. These could be used to
move supplies both there and eventually to the PDJ_
Inspection teams would be required on Routes 127, 154,
6, 13, and 196 to monitor this network.
5. The third major area currently used by the North
Vietnamese for logistic staging into north Laos by the North
Vietnamese is in the vicinity of Dien Bien Phu. To cover
this area, monitoring stations would be needed on
Routes 44 and 19, which comprise the most important part of
the resupply apparatus directed toward Luang Prabang
Province.
6. In addition to the presence of inspection teams on
all of the above-mentioned routes, thorough monitoring
of North Vietnamese personnel and logistics movements would
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require aerial reconnaissance and photography, suOo1` e t:d
7 . In adidit.ion 1-0 supply channels from Nort_ Vietnam,
north Laos is also directly accessible to China via
several major routes, notably Routes 419, '.12, 4021$, and
411. In the past, these routes have carried some supplies
for Communist forces (mainly Pathet Lao) in north.-est
Laos. Since the heavy Chinese presence in the area of
these roads may preclude the use of ground observers
acting in an inspection role
8. Supplies which enter Laos directly from China have
traditionally been used in the northwestern sector. It
is conceivable, however, that by using the Route 19/Cam Ou
River/Route 4 supply corridor, supplies (and men) could move
South toward Luang Prabang or the PDJ, two of the most
contested areas in Laos in recent years. Again, aerial
reconnaissance and clandestine reporting appear to be the
only way to follow such activity.
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