Vietnam tries to split Kampuchea resistance

Vietnam has maintained the tempo of its latest dry-season offensive in Kampuchea (Cambodia) with the capture of another large resistance camp. The unusually large attack on only one of three guerrilla groups hints at a possible strategy to split the Western-backed coalition fighting Hanoi's six-year-long occupation of Kampuchea.

The fighting on the Thai-Kampuchean border is causing China to raise tension on its border with Vietnam.

The resistance camp, known to the Thais as Nong Samet and to the Khmers as Rithisen, was quickly captured on Dec. 25. Some 62,000 of its civilian inhabitants fled into Thailand, bringing the number of new refugees along the Thai side of the border to at least 100,000. A camp official was quoted Thursday as saying that at least 50 guerrillas and 85 civilians were killed in the attack.

Some fighting is said to be continuing around the camp, but the speed with which it was seized must be an embarrassment to the Khmer People's National Liberation Front (KPNLF), the noncommunist group which controls the camp.

The group's officials say that the Vietnamese attacking force numbered about 1,000 men and was supported by artillery, four T-54 tanks, and some armored personnel carriers. One officer in the camp recently said that Rithisen was defended by more than 2,000 fighters. Earlier this month the resistance forces in the camp received another 250 guns from Peking.

Attention is now shifting to the KPNLF headquarters at Ampil. The camp, defended by about half of the group's 15,000 troops, was almost captured earlier this year. It has reportedly been under artillery attack for most of Thursday. The camp's 23,000 civilian inhabitants were said today to be packed up and ready to leave.

Most guerrilla camps are not self-sufficiant in food. They are largely dependent on civilians living in the camps; many of these are their relatives. The civilian refugees are in turn fed by the United Nations Border Relief Organization. Once the civilians and guerrillas are separated, the guerrillas start to have food problems.

The capture of Rithisen means that the KPNLF has lost four of it most important camps in the last six weeks. The size of the offensive is not particularly surprising: For the last month or so, Hanoi has hinted that its military leaders want to launch a major drive against the three groups that make up the Coalition Government of Democratic Kampuchea (CGDK).

More perplexing is why they are concentrating on just one faction. It may well be that they will get around to the other factions - they have until next May before the rains begin to hamper military operations. But among the possible reasons for starting with the KPNLF are:

* The two noncommunist members of the coalition - the KPNLF and the followers of ex-Cambodian Prince Norodom Sihanouk - are politically much more threatening to Hanoi than are the Khmer Rouge. Prince Sihanouk's group, however, is comparatively inactive, and Hanoi still entertains hopes of winning Sihanouk over to their side or at least to a position of neutrality.

* The KPNLF has, in relative terms at least, been more active in its efforts to infiltrate political operatives into Kampuchea this year. This has clearly worried the Phnom Penh government. In a message to Vietnamese and Khmer troops who had destroyed the KPNLF camp of Nong Chan in late November, the Kampuchean government noted approvingly that in doing so they had blocked a major infilitration route.

* Though politically more threatening, the KPNLF is militarily much less formidible than the Khmer Rouge. Military observers estimate that the Vietnamese would need at least one full division (up to 10,000 men) to take some of the major Khmer Rouge bases. The Vietnamese have not needed such large forces against the KPNLF.

* Damage to the KPNLF military organization is also a blow to the hopes of the coalition's Western backers, primarily the United States and the six-member Association of Southeast Asian Nations. These countries want to build up the noncommunists to the point where they are the dominant military force in the coalition. Swift blows to the noncommunists this year would underline the fact that this hope is a long way from reality.

Meanwhile, tension is growing on Vietnam's northern border with China. Chinese officials have said privately that Peking will retaliate against any major Vietnamese operation in Kampuchea by stepping up military pressure on the 715-mile Sino-Vietnamese border.