Bignone took power in 1982 after Argentina's disastrous defeat in the Falklands War against Britain, and left power when democracy was restored in 1983.

Some 30,000 people disappeared -- presumably killed -- under Argentina's military regime, according to Human Rights groups.

Bignone had been sentenced to life in prison for crimes that included murder, torture, abduction, and -- along with another regime leader, Jorge Rafael Videla -- the theft of babies born to political prisoners.

In 2016 he was sentenced to 20 years prison for his role in Operation Condor, in which several South American military regimes collaborated to track down and kill leftist dissidents.

Last year Bignone received another prison sentence for abuses that took place in 1976-1977 when he was head of the Colegio Militar, the army's military school. The victims were young conscripts.

Bignone issued a blanket amnesty in 1983 for dictatorship officials before holding an election won by Raul Alfonsin, a centrist civilian politician.

He also ordered the destruction of all dictatorship-era documents.

The ex-regime officials, however, faced a wave of lawsuits when the amnesty was overturned in 2003.

Last week another regime general, Luciano Benjamin Menendez, nicknamed "the Hyena" and "Jackal" and so brutal he was sentenced to prison 14 times, died in a military hospital. He also was 90.