U.S.-supported rebels have mounted a series of raids against mostly economic targets in the northern Nicaraguan mountains in the past 10 days as debate quickened in Washington over military aid for their sagging guerrilla war.

A Nicaraguan Defense Ministry communique published today charged that the counterrevolutionaries, or contras, made the attacks to attract attention in the United States and counteract reports of declining activity during the past year in the face of increased pressure from the 60,000-man Sandinista Army.

Most of the raids were concentrated just south of the Honduran border. The main U.S.-sponsored guerrilla group, the Nicaraguan Democratic Force, or FDN, operates headquarters and base camps just inside Honduras.

Because of its proximity to those camps, the rugged Nicaraguan hill country was where FDN forces had the first successes, in early 1983, in their fight to overthrow the Sandinista leadership . But it had been largely peaceful since last August, when insurgents briefly captured the roadside town of La Trinidad and then were mauled by Sandinista helicopter gunships.

In what appeared to be the most costly recent strike, rebel forces destroyed a pair of diesel-powered electricity generators yesterday at a regional power substation near Yalaguina. The installation lies 20 miles south of the border on the main north-south highway passing through the garrison town of Esteli 20 miles farther south.

Erasmo Zeledon of the Nicaraguan Electricity Institute said 150,000 people are likely to be without power in the region for about 10 days until emergency generators from Managua can be brought in and hooked up. An institute official in Managua estimated that the equipment destroyed was worth more than $1 million.

Jose Leonida Martinez Gaitan, who commanded a 45-man Popular Sandinista Militia squad defending the substation, said about 100 rebels in three groups attacked at 1 a.m., firing down from surrounding hills with M60 machine guns, 81-mm mortars and rocket-propelled grenade launchers. Several armor-piercing grenades were rocketed into the generators from the edge of the compound, he said, damaging and setting afire the machinery.

Martinez said one technician and one defending militiaman were killed in several hours of fighting, while two militiamen were wounded. The attacking rebels lost one killed and one known wounded, he added. The wounded rebel was found after dawn hiding under a pile of sugar cane with a bullet hole in his left hip and holding his FAL automatic rifle, Martinez said later.

"He shouted, 'I am a peasant. I don't understand why you are grabbing me,' " Martinez smiled. "And that with the FAL in his hand."

The militia squad telephoned for help from an Army garrison at Somoto, about six miles away, Martinez said, but reinforcements arrived only after dawn, when the rebels had already pulled back into the arid mountains. About 250 soldiers in a column of 15 armored troop carriers and several trucks were seen moving north toward the area yesterday.

[In Tegucigalpa, The Associated Press reported, a Honduran military spokesman said 5,000 soldiers were sent to reinforce the border in response to a reported mass deployment by Nicaragua.]

There were no reports of helicopter gunships joining the chase. Use of the Sandinista Air Force's Soviet-made helicopters has been critical in preventing large-scale rebel infiltration over the past year, according to Sandinistas and insurgents.

In addition, the Popular Sandinista Army has organized a dozen Irregular Warfare Battalions equipped for long-range patrolling in the mountains and swift intervention against rebel attacks. An attack Sunday at Totogalpa, just north of Yalaguina, for example, drew immediate dispatch of reinforcements and, according to the Defense Ministry, the killing of six rebel combatants.

Rebel forces struck another economic blow last week with an attack that destroyed tobacco-drying facilities just outside the farming town of Jalapa and near the Honduran border. Several other attacks were reported in the tobacco-farming valley surrounding Jalapa during the week, generating cross-border mortar fire for the first time in months, according to reports.

After a series of such exchanges in 1983 and 1984, the Honduran Army last year imposed tight controls on rebel forces operating along the border. Partly as a result, the main infiltration routes moved eastward toward the more remote and mountainous Bocay River area in Jinotega province, leaving the Jalapa region and more populated border area relatively quiet.

Extensive use of the Irregular Warfare Battalions in the Jinotega mountains, backed by the helicopter gunships, was the main reason the Sandinsita Army was able to restrict rebel infiltration sharply in 1985, according to Sandinista and independent military sources. As a result, this fall's coffee crop was harvested with little disruption, government officials said.

The Defense Ministry communique reported several clashes in the Chontales cattle area last week, indicating some rebels remained active there.