Former dictator Jorge Videla, who ruled Argentina during its "Dirty War," died in prison Friday while serving a life sentence for crimes against humanity. He was 87.

Videla, who led Argentina at the head of a military junta between 1976 and 1981, died of natural causes, according to a medical report.

Videla launched a campaign against the left in which as many as 30,000 people were kidnapped and "disappeared" by the military and suspected opposition figures were swept into secret prisons, tortured and murdered.

Videla, who came to power in a 1976 coup, was sentenced to life in prison in 2010 for the disappearance of 31 prisoners and to another 50 years in 2012 for the theft of children born to female prisoners.

He was convicted in 1985 of a series of abuses under his regime, including kidnapping, torture and murder, but was pardoned five years later by then president Carlos Menem.

The pardon was declared unconstitutional in 2006 as Argentina reopened one of the darkest chapters in its history with a series of high profile trials of former military officials.

Videla showed little remorse for the systematic abuses that occurred during his presidency, a traumatic five year upheaval still being felt today.

"Let's say there were seven thousand or eight thousands people who had to die to win the war against subversion," journalist Ceferino Reato quoted Videla as saying in a prison interview.

"We couldn't execute them by firing squad. Neither could we take them to court," he was quoted as saying.

The military leadership agreed that secretly disposing of their prisoners "was a price to pay to win the war," Videla said, according to Reato in his book "Final Disposition."

"For that reason, so as not to provoke protests inside and outside the country, the decision was reached that these people should be disappeared."

After the interview was published, Videla said he had been misinterpreted. The journalist said the general had reviewed his handwritten notes and approved them before publication.

As recently as Tuesday, in another trial stemming from the period, Videla refused to recognize the jurisdiction of civilian courts in cases "involving the army in the anti-subversive struggle."

He died in the Marcos Paz prison southwest of Buenos Aires, where he spent his final days in a spartan cell with a wooden cross on the wall.

"Last night he didn't feel well. He didn't want to eat and this morning they found him dead in his cell," Cecilia Pando, the head of the Association of Family and Friends of Political Prisoners, told reporters.

Videla was the head of the army when the military overthrew Isabel Peron, the widow of Juan Peron, at a period of mounting instability, punctuated by guerrilla attacks and a surge of killings by right-wing death squads.

As the head of the three man junta that assumed power, Videla suspended the constitution, outlawed political parties and imposed censorship on TV and radio in what was called a "Process of National Reorganization."

He unleashed the military on the leftist guerrilla groups active in Argentina in a campaign of repression that soon spread far beyond their ranks.

Family members, suspected sympathizers, labor organizers, politicians, clergy, students, journalists, artists and intellectuals were killed or secretly imprisoned in clandestine concentration camps.

The regime's trademark became the unmarked Ford Falcon sedans that hooded agents used to drive their captives to some 500 detention centers set up around the country.

Among the victims were French nuns Alice Domon and Leonie Duquet, Catholic bishop Enrique Angelelli, Swedish student Dagmar Hagelin, the union leadership at Ford and Mercedes Benz, and even members of Argentina's diplomatic corps.

Argentina's military also joined forces with like-minded dictatorships in Chile, Brazil, Bolivia, Uruguay and Paraguay under "Operation Condor," sharing intelligence and helping capture each other's political enemies.

Rail-thin and with a rigid military posture, Videla in his heyday cut a somber, unsmiling figure with large dark eyes, a brush mustache, and hair slicked back from a bony face.

He delivered speeches in a strident manner and often appeared uncomfortable in public, wringing his hands as a nervous tick played across his cheeks.

Videla put Argentina's economy in the hands of a civilian group called the "Chicago Boys" because of their admiration for Milton Friedman, a conservative American economist whose ideas were also put into practice in Chile.

Although aligned with the United States, Videla was at loggerheads with US president Jimmy Carter over the regime's human rights abuses and for refusing to join a US-backed grain embargo against the Soviet Union.

In 1981, Videla handed over power to General Roberto Viola to begin the slow transition to democracy.

But General Leopoldo Galtieri ousted Viola in a palace coup and took Argentina to war and ultimately to a humiliating defeat against British forces in the Falkland Islands the following year.