Marxist group sharpens Salvador guerrillas' threat to Army

Two guerrilla fighters in green fatigues deftly type out orders in the one-room town hall. Several M-16 automatic rifles are stacked along the cinder-block walls.

Canteens, field packs, ammunition belts, and assorted pieces of camp equipment - all made in the United States - lie scattered around the expropriated command quarters.

La Laguna, a small community rimmed by sharp-nosed volcanic peaks, is a guerrilla town. Rebel graffiti covers the walls of the town and guerrillas freely meet in the streets and lounge in the main square.

This town and much of Chalatenango Province is held by the Popular Liberation Front (FPL), militarily one of two strongest rebel groups.

The FPL has only in the past year joined the Farabundo Marti National Liberation Front in coordinated military attacks on El Salvador's Army. But by switching its tactics from small-scale raids mounted on its own to large-scale movements staged in coordination with other liberation front members, the FPL has helped to make the guerrilla movement more aggressive and a larger threat to the Salvadorean Army.

''When the (Salvadorean) soldiers look up and see those mountains, they are demoralized because they know we are there,'' one rebel proudly asserts.

In the chill morning air, FPL guerrillas congregate here in small groups, preparing to leave on their daily patrols through Comalapa, La Junta, Concep-

cion Quezalte- -peque, and other provincial communities. The fighters carry automatic weapons and are dressed in pirated Army fatigues.

Columns of guerrillas travel through the volcanic peaks carrying their heavy US-made M-50 machine guns and mortars on mule- and horseback. They say most of their weapons, including the heavy caliber equipment, are captured from the Salvadorean Army.

There are an estimated 9,000 to 11,000 guerrillas operating in El Salvador, according to the United States Embassy. The FPL accounts for 2,000 of these; its forces are spread out over Chalatenango, Cabanas, and Cuscatlan provinces. FPL troops are organized in elite ''vanguard units,'' with some less skilled units acting as ''guerrilla columns'' in the countryside. The FPL also has local militias and a small ''urban front'' terrorist group that operates in the cities. One of its urban fronts, the ''Clara Elizabeth Ramirez'' group, claimed responsibility for the killing of a US military adviser, Navy Cmdr. Albert Schaufelberger, in May 1983.

Although the FPL has joined the Farabundo Marti National Liberation Front in military strategy, it remains separate politically. It is perhaps the most Marxist-Leninist of the guerrilla groups, and its symbol is the Russian hammer and sickle, which members have emblazoned on buildings throughout Chalatenango.

The FPL has long been the most recalcitrant member of the FMLN, which is made of five rebel groups. FPL founder Salvador Cayetano Carpio was disdainful of the military capabilities of the other rebel groups, and favored a ''prolonged popular war,'' modeled on the North Vietnamese model, to the FMLN's military-political approach to winning the war.

The doctrine of prolonged popular war, calls for long-term, low-intensity fighting in an effort to wear down the opposing Army over a period of years. And by 1983, even factions within the FPL were fighting bitterly about the strategy, which did not permit major military offenses.

Melida Amaya Montes, Carpio's senior deputy, finally broke with the FPL founder's ideology.

Her confrontation ended brutally on April 6, 1983 in a guerrilla safe house outside Managua, Nicaragua. In the early morning hours, FPL lieutenants loyal to Carpio, broke into her home, savagely stabbing her to death.

Nicaraguan Interior Minister Thomas Borge confronted Carpio with his involvement in the murder a week later, diplomatic officials say. The FPL leader was apparently given the option of suicide or exposure of his involvement in the killing, these sources say. He chose suicide.

''With the death of Carpio, major changes took place in the FPL,'' says guerrilla leader ''Walter,'' who commands a battalion of 300 fighters. ''We were freed from a demagogue who had put himself above the cause and were able to begin working together with the other groups in the FMLN.''

After Carpio's death in the spring of 1983, the FPL leadership fell in the hands of a younger generation of fighters. The new leaders have drastically revised, if not abandoned, the prolonged war strategy. The group's Central Command, composed of more than 25 of the top FPL commanders, has taken the line of slain leader Montes. They say they now favor a negotiated end to war and a military strategy that unites their efforts with the rest of the liberation front.

There may be a sharp difference between rebel politics and rebel military strategy, however. The Faribundo Marti National Liberation Front, the guerrilla fighters, seems to be far better integrated than the purported political wing the guerrilla movement.

The political wing, the Revolutionary Democratic Front, is composed of former Christian Democratic leaders such as Guillermo Ungo and Ruben Zamora. These men say they favor a liberal democracy.

But many guerrillas have never heard of the Revolutionary Democratic Front, much less its political leaders.

''Ruben Zamora,'' one rebel in La Laguna says, then pauses a moment. ''Wasn't he one of those guerrilla commanders killed a few years ago?''

''When we take power it will be the peasants who decide how things are run,'' says one guerrilla, standing on a sloping road outside La Laguna.

''We used to live down there,'' says another, pointing to the wide expanse of water known as the Cerron Grande. ''Then they built the dam and we lost our homes.''

The construction of the giant dam in 1974 forced some 15,000 peasants off their lands without compensation and augmented the emerging FPL forces.

''The cotton estates will be turned over to us so we can make clothes for the people. There will be no private property,'' says one of the rebels.

These fighters say they want want to turn expensive homes in the suburbs of San Salvador over impoverished people displaced by the war.

The FPL has also incorporated elements of the Armed Forces of Liberation into its ranks. That group represents the Moscow-line Salvadorean Communist Party.