DULCE NOMBRE DE MARIA, EL SALVADOR, NOV. 6 -- Cradling his M16 rifle as he lounged in a gazebo in the village square here, Jorge, a 27-year-old Salvadoran Army sergeant, gestured toward the green mountains a few miles to the north.

"The rebels are in those hills," he said. "But because of the cease-fire, we can't chase them."

Less than 24 hours after President Jose Napoleon Duarte declared a unilateral cease-fire in the government's eight-year-old war with the Marxist-led rebels, the guerrillas had already committed one act of sabotage, and Jorge and his men appeared frustrated.

Shortly after 1 a.m. today, the rebels blew up an electricity pylon near here, cutting off power to this village of several thousand people in northern El Salvador's Chalatenango province. The action was in line with a rebel communique distributed today in which the Farabundo Marti National Liberation Front, known by its Spanish initials FMLN, rejected the cease-fire and announced that "the order for combat is given."

The communique accused the military of expanding its troop deployments in the countryside and said its forces would act against the "operations and repressive actions of the enemy." It did not take long for the guerrillas to carry out the threat.

Near the town of San Vicente in the central part of the country, four soldiers were reported killed in a rebel ambush today.

At least 10 primary power transmission lines and four secondary lines were destroyed during the night, affecting half the electricity transmission facilities in the country and blacking out parts of the capital, according to Gen. Abdul Gutierrez, the head of the national electricity company. He called it "the worst span of sabotage" since the war began.

"Up to now I don't understand it," Jorge said when asked about the unilateral truce. "A cease-fire is supposed to be from two sides.

"We used to patrol those mountains before, but now we're only on the defensive," he said. "For us it's dangerous. When we're on patrol looking for them {the rebels}, we have the advantage."

The sergeant's comments appeared to typify what seems to be, at best, a lukewarm response from the military to Duarte's cease-fire call in compliance with a Central American peace plan. He has ordered the 56,000-member Salvadoran Armed Forces to stop offensive actions for 15 days, until midnight Nov. 20, and to get special permission for any use of artillery or aircraft in responding to rebel attacks on military positions.

In a speech yesterday, Duarte called on the FMLN's estimated 6,000 guerrillas to respect the truce. He also warned the rebels not to move around in uniform or with weapons or to transport arms.

In an interview today, Col. Jose Humberto Gomez, the commander of the 4th Infantry Brigade headquartered at El Paraiso, about six miles south of here, said this meant patrols by rebels in uniforms or with arms would be considered "violations" of the government cease-fire. He was evasive when asked what one of his units would do if it crossed paths with a rebel patrol.

"I believe the cease-fire is worth trying because it does not affect our constitutional obligation to guarantee the security of the population," Gomez said. He said that in accordance with the unilateral truce, his men would conduct only "defensive patrols" within six miles of their "bases." But he declined to say how many bases his brigade has and suggested that he regards a base as any place his men are posted.

As far as he is concerned, Gomez said, "defensive" patrolling means that "we are not looking for the terrorists {guerrillas}."

The public reaction to the government cease-fire in this village, which is frequently patrolled by government troops, seemed muted.

Daisy Valle, a 25-year-old mother of two, said she did not think that much had changed.

"God willing, this will turn out to be something that advances us toward peace," she said as she nursed her baby beside a tortilla stand next to the village's Spanish-style church.

She said she returned to this village eight months ago from the United States, where she worked at a McDonald's restaurant in Los Angeles during a three-year stay as an illegal alien. She said her Salvadoran husband, who stayed behind to work, sends her $150 a month from his job at a plastic-straw factory in New York.

Since she has been back, she said, she has seen the FMLN guerrillas in this village only twice.

Once was last Saturday, when they painted slogans in red on several walls and held a meeting with the villagers.

Now the Army is here, guarding against the rebels' return. Next to the local office of the state telecommunications company, a soldier in battle gear manned a machine gun, aimed toward the hills in which the rebels are thought to be hiding. A few yards away, a drunken man lay on the sidewalk, taking a late-morning siesta. On the wall beside the machine gunner's position a red-painted slogan read, "Viva el FMLN."

For Jorge, who wears camouflage fatigues and an olive-green headband, the prospects for peace do not look bright.

"For their part, I don't see it," he said. "The guerrillas only want war."