130. Memorandum From the Director of Intelligence and Research (Hughes) to the Deputy Assistant Secretary of State for Far Eastern Affairs (Green)1
SUBJECT
- Viet Cong Use of Cambodian Territory
As requested by FE/SEA and S/VN we have examined the airgrams, CAS report [less than 1 line of source text not declassified] and the photographic intelligence report mentioned in Saigonʼs telegram No. 1898 of April 3, 1964, as well as other materials relating to Viet Cong use of Cambodian territory for the past 18 months.2 On balance we believe that the conclusions of RFE Research Memorandum No. 35 of August 7, 1962 (attached) are still substantially valid: i.e., there is still no firm evidence to substantiate numerous official GVN charges and reports the Viet Cong make extensive use of Cambodian territory as a base for operations in Vietnam; there is, nevertheless, no doubt that the Viet Cong make limited use of Cambodian territory as a safe haven and for infiltrating cadres, supplies, and funds. The Viet Cong probably cross the frontier with somewhat greater frequency and ease at present since they control areas along the Vietnamese side of the frontier more effectively than they did in 1962. They also probably bivouac in Cambodian territory for varying periods of time. However, evidence that the Viet Cong have established and maintain permanent bases in Cambodia has not been effectively substantiated.
Saigon Embassy Airgrams No. A–686 of May 6, 1963 and A–728 of May 16, 1963, as well as Airgrams No. 296 of December 3, 1962 and several [Page 301] CAS documents contain numerous reports alleging illegal movements back and forth across the border by various groups, including Viet Cong. These reports, particularly those found in South Vietnamese newspapers may be somewhat exaggerated, but they are so frequent and consistent as to be probably true in large measure. US advisors have reported seeing Viet Cong units fleeing into Cambodia, and the Cambodian Government has announced that Viet Cong and other border crossers, have been repulsed or captured occasionally.
Embassy Airgrams No. A–808 of June 20, 1963 and A–251 of October 10, 1963 report the flow of munitions material and arms and ammunition from Cambodia into Vietnam, during the period March 30 to September 23, 1963. During this period, 16 tons of explosive materials were reportedly seized by the GVN. Since that time only two seizures have been made (December 1963 and March 1964) producing a total of three tons (Saigon telegram No. 1985 of April 14, 1964). Whether this indicates that the flow of materials really has dropped or that the Viet Cong have now found means of avoiding GVN surveillance is not clear.
Reports that the Viet Cong maintain logistical installations, training camps, concealed bivouacs, rest camps, and even farms on the Cambodian side of the border are contained in Airgrams No. A–296, 686, and 728, and in CAS reports. GVN military commanders on the border areas and their US advisors are convinced that the Viet Cong maintain permanent bases on the Cambodian side of the frontier. CAS report [less than 1 line of source text not declassified] of October 28, 1963 [less than 1 line of source text not declassified] stated that [less than 1 line of source text not declassified] the Viet Cong were maintaining military training bases and workshops in an area covering approximately 25 square kilometers of the “parrotʼs beak” area of Cambodia opposite Long An and Kien Tuong Provinces. (XS 290 950) According to Saigonʼs 1898, aerial photography of this region “confirmed the existence of what appears to be a military base straddling the border in this area,” although the installations photographed are not exactly at the same locations as those given in the CAS report. The Detailed Photographic Interpretation report of this photography (attached) contends that “a heavily defended military area,” covering 9 square kilometers, is located in this area, including command, storage, and supply facilities, numerous foxholes, AW emplacements and trenches. However, the detailed annotations indicate that most of the identifications are only “possible” and do not confirm that these installations are in fact Viet Cong. According to Saigonʼs 1898, Cambodian officials have told the Army Attaché at Phnom Penh that this area has been abandoned, which may either indicate that the Viet Cong have left or that these were former RKG installations. Thus the report that the Viet Cong have a base in this area does not seem to be confirmed. Saigonʼs 1898 [Page 302] indicates that other reports of Viet Cong installations inside Cambodian territory have not been substantiated.
Conclusions: While it seems clear that Viet Cong use the Cambodian border area as a sanctuary and probably bivouac there for varying periods, we have as yet no effective confirmation of reports that they have permanent military bases there. A well-publicized attempt in late 1961 to prove that the Viet Cong had established bases in Cambodia was unsuccessful and caused embarrassment to both the GVN and the United States, setting back GVN efforts to enlist RKG cooperation in control of the border.3