Provincial police said tonight that two men who were listed by Argentine human rights groups as victims of military abduction were killed in a shootout Saturday. Rights leaders said they feared a new wave of repression by the armed forces.

Police said Osvaldo Cambiasso, 42, a Peronist Party activist, and Eduardo Pereira Rossi, 33, were killed after they opened fire on police along the Pan American Highway in Buenos Aires Province. They said Pereira Rossi was an ex-press secretary in Mexico for the once-powerful Montonero guerrillas, which claimed to follow the late president Juan Peron.

However, human rights groups here, in pressing since Saturday for release of the two men, said they have evidence that both men were kidnaped from a bar in downtown Rosario that morning by Army members dressed as civilians. The two men were ushered into a van without license plates and driven off.

Such abductions occurred frequently in the late 1970s during the ruling military's undeclared war against leftist guerrillas but had ended in recent years. The failure of the generals to give an accounting of the earlier "disappearances" has become a divisive issue here as armed forces prepare to bow out after elections later this year.

"We have confidental but absolutely reliable information that the Army killed them, then tried to pass their bodies to the police in Zarate in Buenos Aires Province to make it look like they were killed in a shootout," said Emilio Mignone, head of the Center for Legal and Social Studies.

Mignone said it was "absurd" that the police would not have been able to identify Cambiasso until today, as he had spent seven years in Argentine jails. kept the bodies this long trying to figure out" how to explain the deaths, he said.

Earlier this evening, human rights supporters went to the Ministry of Interior to file a protest in the case, but they were not received. An hour later the provincial police released their statement.

Cambiasso, who was released from jail last year, recently acquired Italian citizenship, human rights groups say, and yesterday the Italian consul in Rosario, about 180 miles north of here, met with Army officials to discuss the case. It is not unusual for Argentines of Italian ancestry to acquire dual citizenship.

International and local human rights groups say that between 6,000 and 15,000 people vanished beginning while the Peronists were in power and accelerating after the military coup of 1976. In a "final report" issued by the Argentine junta last month, the military said that all those disappeared people who are not either living abroad in exile or hiding in Argentina are dead.

Last night, Mignone's center, one of the most important rights groups here said Cambiasso's abduction "represents the vigilance of the repressive apparatus."