Border Fighting and Negotiations, 1975-76
Fighting began immediately after the fall of Phnom-Penh on April 17, 1975, and that of Saigon on April 30, which ended the civil wars in Cambodia and Vietnam respectively. According to the Vietnamese statement of April 7, 1978, Cambodian troops encroached on Vietnamese territory in a number of places from Ha Tien (on the coast) north-east to Tay Ninh on May 1, 1975, causing heavy casualties. The Cambodian statement of Dec.31, 1977, on the other hand, alleged that "immediately after Cambodia was liberated" Vietnamese troops had shelled the border areas and set up bases on Cambodian soil in the north-eastern Ratanakiri and Mondolkiri provinces and in other areas.
Fighting also took place during this period on the offshore islands, as was reported at the time. According to the Vietnamese statement, Cambodian troops landed on Phu Quoc on May 4, and six days later launched attacks from the mainland and from the Cambodian island of Poulo Wai on the Vietnamese island of Tho Chu The Vietnamese forces expelled them from Tho Chu on May 25 and pursued them as far as Poulo Wai, which they temporarily occupied. The Vietnamese report was confirmed by refugees from Phu Quoc who had escaped to Australia, and who stated that the Cambodians had made many harassing attacks on the island early in 1975.
A CPK delegation headed by Mr Pol Pot visited Hanoi on June 11-14, 1975. The Cambodian version of the talks said that the purpose of the visit had been to settle the border problem, but the Vietnamese had not taken up the matter for discussion. The Vietnamese version, on the other hand, said that the Cambodians had suggested the conclusion of a treaty of friendship, but had not requested immediate negotiations on the border question.
The situation apparently remained peaceful for the next six months, but later Vietnamese statements alleged that in December 1975 Cambodian troops had attacked and occupied Vietnamese territory in Gia Lia-Kontum and Dac Lac provinces, and that further incidents had occurred in the early months of 1976.
An official of the An Giang provincial government told the correspondent of Le Monde in March 1978 that over 1,000 Cambodians who had taken refuge in the province had been handed over to the (Cambodian) Takeo provincial authorities in December 1975. At that time, he stated, the situation on the border had still been friendly, and the minor incidents which had occurred had been settled through discussions between the provincial authorities on the two sides.
The Two Governments agreed in April 1976 to hold discussions in June in preparation for the signing of a border treaty. At a preliminary meeting in Phnom-Penh on May 4-18 it was decided to follow the map of the land border used by the French before 1954 and to set up liaison committees to investigate and settle border conflicts, but differences arose over the sea border. The Cambodians proposed that the Br,vi, Line should be retained as the border, but the Vietnamese, while prepared to accept it as the demarcation line in respect of sovereignty over the islands, refused to regard it as demarcating territorial waters. The meeting was adjourned at Cambodia's request and was not resumed, although the Vietnamese claimed that they had proposed several times that it should be. The number of border incidents nevertheless decreased over the next 10 months.
Intensification of Border Fighting, March to December 1977
The situation gravely deteriorated from March 1977 onwards. According to an official Vietnamese document published on Jan. 6, 1978, the Cambodian forces made raids into the Vietnamese provinces of Kien Giang and An Giang on March 15-18 and 25-28, 1977, along a sector nearly 100 km long from Ha Tien (Kien Giang) to Tinh Vien (An Giang). Strong Cambodian forces launched concerted attacks on Vietnamese Army posts and on border villages in An Giang between April 30 and May 19, killing 222 civilians, and shelled Chau Doc, the provincial capital, on May 17. These reports were corroborated by Vietnamese refugees reaching other Asian countries, who stated that the civilian population had been evacuated from Ha Tien on May 16 and from Chau Doc on the following day after the two towns had been shelled.
In a letter of June 7, which was conciliatory in tone, the Vietnamese Government proposed that a high-level meeting to settle the border question should be held as soon as possible in Phnom-Penh or Hanoi (the capital of Vietnam). The Cambodian Government replied on June 18 that it would be better "to let some time elapse for the situation to return to normal" before any such meeting took place.
According to the Vietnamese document, fighting continued at intervals throughout mid-1977. Cambodian troops shelled Ha Tien on June 11 and 14 and Chau Doc on July 16-18, and attacked border posts in Kien Giang on June 14. Mr Thanin Kraivichien, then Prime Minister of Thailand, stated on Aug. 6 that "the conflict between Cambodia and Vietnam on the border dispute is far worse than that on the Cambodian-Thai border", and that "they even have planes bombing on both sides". A Bangkok Post report of Sept. 1said that Vietnamese aircraft had carried out bombing raids up to 15 miles into Cambodia and had undertaken long-range reconnaissance flights, but made no reference to bombing by the small Cambodian Air Force.
The fighting, which had previously been confined mainly to Kien Giang and An Giang provinces (i.e. between the Mekong and the coast), spread in mid-1977 to the Parrot's Beak area and apparently to the Central Highlands of Vietnam. The Vietnamese document mentioned Cambodian attacks on villages in Tay Ninh and Long An provinces (bordering on the Parrot's Beak) on Aug. 30 and Sept. 8-10, as well as continued raids into An Giang. Although it did not refer to the Central Highlands, Phnom-Penh radio suggested several times at the end of July and in the first week of August that fighting was taking place on the borders of the neighbouring Mondolkiri and Ratanakiri provinces.
The scale of the fighting greatly increased in the second half of September 1977-this development coinciding with Mr Pol Pot's resumption of the premiership and his visits to China and North Korea. The Vietnamese document of Jan. 6, 1978, which was supported by reports from US intelligence sources, stated that from Sept.24 onwards Cambodian forces totalling about four divisions had launched continuous attacks along the entire border of Tay Ninh province, and that over 1,000 civilians had been killed or wounded in this area between Sept.24 and late November. The Cambodian statement of Dec.31, on the other hand, alleged that since September Cambodia had been invaded by several Vietnamese divisions, supported by hundreds of tanks and by artillery and aircraft.
A Cambodian statement of Jan. 6, 1978, alleged that the invasion had taken place in three phases: in September 1977 the Vietnamese had advanced 20 km along Highway 7 into Kompong Cham province and occupied the towns of Memot and Krek; (ii) in November they had also advanced along Highway 1 into Svay Rieng province (the Parrot's Beak), occupying positions 10 km north and east of the town of Svay Rieng itself; and (iii) in December they had advanced up to 30 km into Takeo province, and up to 30 km into the coastal province of Kampot. During this period they had also repeatedly shelled and intruded into the northern provinces of Kratie, Mondolkiri and Ratanakiri. The statement alleged that "wherever they have intruded they have destroyed the administrative apparatus of the Cambodian people, killed the cadres of the Cambodian people's administrative power at all levels, and installed in their places the remnants of the hooligans of the old Cambodian society, appointing them as commune and village chairmen".
It was impossible to verify these contradictory reports, as at that time foreign journalists were excluded from Cambodia and were not allowed to visit the border areas of Vietnam. Reports from diplomatic and intelligence sources in Bangkok, however, generally agreed that in December Vietnam had reacted to Cambodian provocation by launching a counteroffensive into Cambodia.
Defeat of Vietnamese "Invasion" claimed by CambodiaThe two sides' reports of the fighting in January 1978 remained completely contradictory. The Cambodians claimed to have expelled the Vietnamese "invaders" after a. major victory on Jan. 6, whilst the Vietnamese continued to report Cambodian incursions into their territory.
According to the Cambodian version of events, the Vietnamese troops in Kompong Cham province advanced along Highway 7 on Jan. 1 to the Pratheat crossroads, 30 km from the border, and spread out 20 km north and south of the road. On the same day, however, the Cambodian forces began a counter-offensive along the whole front. In Kampot province the Vietnamese were "basically wiped out" on Jan. 1, the remainder being mopped up along the border two days later. In Takeo the Cambodian forces attacked on Jan. 2 and reached the border on the following day, destroying two enemy divisions. In Svay Rieng province the Cambodians attacked on Jan. 4; captured Chak (10 km north of Svay Rieng town) on the following day; wiped out the enemy almost completely on Highway 1 on Jan. 6; and destroyed the remaining Vietnamese forces on Jan. 8. In Kompong Cham province the Cambodians launched co-ordinated attacks on All sides during the night of Jan. 4-5, completely routing the Vietnamese. Phnom-Penh radio also claimed on Jan. 6 that the Vietnamese had been "routed shamefully" in Kratie province, and on Jan. 7 that they had been wiped out in Mondolkiri, where they had entered Senmonorom, the provincial capital; these were the first reports that Vietnamese troops had invaded these two provinces.
A Cambodian broadcast on Jan. 6 claimed that over 29,000 Vietnamese troops had been killed or wounded, five divisions routed and 117 tanks destroyed or put out of action, for the loss of only 470 Cambodians killed and 1,222 wounded. It also alleged that on the Krek battlefront communications in Russian between Europeans and Russian-speaking Vietnamese had been overheard, and that the corpses of two Europeans had been seen on a tank put Out of action. Messages from Prince Sihanouk and Mr Penn Nouth congratulating the Government on its "victory" were broadcast on Phnom-Penh radio on Jan. 8.
Vietnamese sources meanwhile continued to report Cambodian raids on Vietnam. The official Vietnam News Agency stated on Jan. 7 that Cambodian troops had made several attacks in force on Dong Thap, An Giang and Kien Giang provinces during Jan. 1-3, and had "compelled the Vietnamese armed forces to use their right of legitimate self-defence to reply in an appropriate way and drive far away from the Vietnamese border the Cambodian Army units which had encroached on Vietnamese territory", thereby admitting that Vietnamese forces had entered Cambodia.
Reports from intelligence and diplomatic sources in Bangkok agreed that strong Vietnamese forces had entered Cambodia in December and at the beginning of January, and were gradually withdrawn in January and February, but regarded the Cambodian claims with extreme scepticism. Le Monde described them as "completely incredible", whilst TheTimes commented: "There is little doubt that the Cambodians have suffered a bloody defeat and that their radio claims have been made solely in an effort to boost flagging morale."
Thousands of Cambodians fled into Vietnam after the entry of the Vietnamese troops. The Office of the UN High Commissioner for Refugees, to which Vietnam had appealed for help in April, stated in June that according to the Vietnamese Government's estimates 150,000 Cambodians and 170,000 persons of Vietnamese origin normally resident in Cambodia had entered Vietnam, whilst 750,000 Vietnamese had been displaced from the frontier region.