Khmer Rouge begin to stake out claims to Kampuchea's interior

Five years after their takeover of Kampuchea (Cambodia), it appears that the Vietnamese have realized they are in for a longer conflict with anti-Vietnamese forces than they had first planned.

The Vietnamese are thus pulling back to key defensive points in an effort to cut the human and monetary costs of the war.

The Khmer Rouge, the largest anti-Vietnamese force, have taken advantage of the opportunities created by Vietnam's inability to continue pressing the war. The army of former Kampuchean leader Pol Pot has been invigorated with fresh recruits and Chinese supplies.

Although this situation marks a new phase of the war, it brings Kampuchea no closer to peace. Both sides have become more firmly entrenched in a war destined to be fought for a long time to come.

It is hard to evaluate Khmer Rouge claims about their level of activity deep in the interior of Kampuchea. According to Khmer Rouge spokesman Ieng Sary, bases have been established in the north at Phnom Koulen, on the far periphery of the Angkor Wat region, and near the Thai-Lao-Kampuchean border. From these bases, says Mr. Ieng, Khmer Rouge soldiers were able to operate widely in Kampuchea's central plains for the first time in 1983, and launch attacks near the cities of Siem Reap, Kompong Thom, and stretches of Highway 6.

If true, this would represent the first major theater of resistance activity in open areas, away from mountain and jungle strongholds, and away from the protection of the Thai border.

(The Khmer Rouge have waged a major attack against the Vietnamese-occupied town of Siem Reap, according to Khmer Rouge Radio monitored in Bangkok on Jan. 31 and reported by UPI. The guerrillas reportedly overran the town, about 90 miles from the Thai border and near Angkor Wat, occupying the town for one night. Casualties were 50 Vietnamese soldiers killed and 23 wounded, according to the Khmer Rouge. No guerrilla casualties were reported. It was one of the largest assaults in five years of fighting, reports UPI.)

One Bangkok-based Japanese journalist, Naoki Mabuchi, trekked for 10 weeks with the Khmer Rouge during the 1983 dry season, covering more than 1,000 kilometers (625 miles) on foot.

''I was able to cross Highway 6 without problem. We reached Tonle Sap and were able to travel several kilometers across it by boat in broad daylight,'' he reported.

''Along Highway 6, I observed many villages that appeared to be under control of the Democratic Kampuchean army. It was only a minority of villages that were controlled by the Vietnamese.''

A diplomatic source in Bangkok said he was not surprised by the distances Mabuchi was able to travel escorted by the Khmer Rouge, noting that reliable reports indicated that ''the Khmer Rouge are able to operate in areas covering more than half the country. But . . . how much they are actually able to control is harder to say.''

Despite the signs of new vitality on the part of the guerrillas, there is no doubt that the Vietnamese remain in firm control of the major cities which now hold most of the population, as well as what remains of the country's road and rail infrastructure.

Even Ieng Sary acknowledges that the ''chances of winning a military victory are small.''

Moreover, as the resistance grows stronger, the Vietnamese may well respond with tougher military measures. Up until now, Hanoi has used very little air power. If the Khmer Rouge expand their operations in the open areas of Kampuchea's plains, Ieng Sary raised the possibility of Vietnamese helicopter gunship attacks.

Dr. Thiounn Thoeun, the Democratic Kampuchean health minister, observed in an interview: ''We see increased use of chemical weapons by the Vietnamese when they have difficulty attacking one of our strongholds through other means.'' While the chemical warfare allegation remains difficult to document, Dr. Thiounn insists that chemical agents are weapons of last resort used by the Vietnamese, especially in the dry season.

In addition to their growing numbers - recruits in 1983 numbered 15,000, according to Ieng Sary - the Khmer Rouge are now able to operate regular military training bases for the first time. Although formal instruction for new recruits usually lasts no longer than a month and is simplistic by Western standards, it now includes practice with live ammunition.

While the style of warfare carried out by all Khmer Rouge forces is chiefly guerrilla in nature, their military structure differentiates between the regular army (the bulk of the forces) and two types of guerrilla units.

One is the small commando group which operates far from its regular army base to attack roads, bridges, railway lines, and other targets in the interior of the country. Another type is attached to civilian villages and engages in local forays. Both types of guerrilla units have apparently absorbed many of the young men resettled from the refugee camps in Thailand over the last two years.

Next: Civilian life in Khamer Rouge - controlled areas