BUENOS AIRES, DEC. 29 -- Two former dictators who led the 1970s "dirty war" against a leftist insurgency and a rebel leader whose movement inspired the repression were freed today by government pardons.

The onetime dictators, former army Gens. Jorge Videla and Roberto Viola as well as other officials of the 1976-1983 military dictatorship left the Magdalena military prison, 62 miles south of here, the government news agency Telam said. The two former military presidents were taken away in a helicopter. Also released was Montonero guerrilla founder Mario Eduardo Firmenich, who walked out of Villa Devoto jail and was driven away in a car, the news agency said.

Videla and Viola were among 11 former officials, mostly generals convicted of torture and other rights abuses and jailed in 1984, who were pardoned under an order signed by President Carlos Menem today. The president made no official statement, Telam said.

Menem, who last year freed 39 other generals and 64 terrorists, said earlier that today's releases would "definitely close a sad and black stage of Argentine history."

The pardons, however, will reopen wounds for many Argentines. Recent polls have shown up to 80 percent of the population opposed to freeing the men who symbolized a painful period in which thousands were spirited away by men in civilian clothing and never seen again.

The army said its unconventional war in the late 1970s and early 1980s was the only kind possible to fight leftist insurgents. Human rights groups say up to 30,000 people died in a campaign of genocide.

"This is a very sad day for Argentina," said former president Raul Alfonsin. Politicians, clergy and human rights activists planned to demonstrate Sunday across this nation of 31 million people.

Those freed also included two former Buenos Aires police chiefs, Ramon Camps and Pablo Ricchieri; dismissed Adm. Emilio Massera; and former army chief of staff Carlos Suarez Mason, who was extradited from the United States in 1988.