Brooklyn Rivera, a top leader of Nicaragua's Indian guerrillas, has been wounded in a Sandinista attack and is hiding out in remote hills on the Caribbean coast of Nicaragua, his aides reported today.

Officials of Rivera's insurgent group, Misurasata, expressed belief that his clandestine presence inside Nicaragua was revealed by a Sandinista infiltrator and that an attack launched a week ago by the Popular Sandinista Army constituted an attempt to kill or capture the rebel leader. If true, they added, this will cast a dark shadow of uncertainty over Rivera's recent moves to conclude a separate Indian peace agreement with the Sandinista government in Managua, perhaps ending them for good.

"Our struggle is irreversible," said Rafael Zelaya, a Rivera deputy in the Costa Rica-based Misurasata rebel organization.

Zelaya and another Misurasata official, Guillermo Espinoza, said Rivera sneaked from here into Nicaragua on Dec. 22 or 23 to speak to guerrillas and Indian villagers about his contacts late last year with the Sandinista leadership. Rivera visited Nicaragua openly in October for talks with Sandinista officials and held more discussions in Bogota, Colombia, last month with Luis Carrion of the Sandinistas' ruling National Directorate.

Rivera explained then that Nicaragua's Miskito, Rama and Sumo Indians have different goals in fighting the Sandinistas from those of the Nicarguan Democratic Force, the main U.S.-backed rebel group based in Honduras. But Indian demands for autonomy as part of a separate accord have gone unheeded, aides here said, and Rivera refused to agree to a cease-fire in the northeastern Nicaraguan wilderness where his forces have raided Sandinista forces for the past two years.

The other, larger Indian rebel group, Misura, opposed Rivera's peace effort, remaining in close alliance with the Nicaraguan Democratic Force, or FDN by its Spanish initials. The Misura leader, Steadman Fagoth, operates from Honduras in collaboration with FDN officers who until June were financed by the CIA.

Foreign Minister Edgardo Paz Barnica of Honduras yesterday urged that Fagoth's operations be expelled from Honduras, accusing the Misura leader of violating Honduran sovereignty by calling for international mediation over Sandinista prisoners in his custody, according to reports from Tegucigalpa. It was unclear whether this represented a change in Honduran cooperation with the rebels, which in the past four years has been decided and carried out by the armed forces command rather than the Foreign Ministry.

It was to discuss the faltering negotiations with Managua that Rivera traveled secretly to Nicaragua, holding meetings with combatants and civilian Indian leaders in settlements along the Atlantic Coast, Espinoza said. But soon after Rivera addressed a meeting seven days ago at Tasbapauni, on Pearl Lagoon about 40 miles north of Bluefields, Sandinista forces opened a concentrated attack using airplanes and patrol boats along with ground troops, he added.

As he sought to flee the area, Rivera was wounded about three days ago, the aides reported. Zelaya said rebel radio communications since then have reported that Rivera was transported by guerrillas to a mountain hideout. The communications have not, however, described his injuries or how serious they are. Misurasata has dispatched a rescue team to try evacuating Rivera to Costa Rica for treatment, he added.

Rivera is believed to be the first high-ranking rebel political leader to be wounded in combat in Nicaragua, although Eden Pastora, leader of another rebel group, was wounded by a bomb last spring during a news conference just inside Nicaragua from Costa Rica