Former Argentine junta leader Reynaldo Bignone has been sentenced to 20 years in prison for crimes committed under Operation Condor – a conspiracy between South America’s dictators.
Bignone and 17 other military officers were found guilty by a court in Argentina after a three-year trial.
Many left-wing activists were kidnapped and killed in Argentina, Uruguay, Brazil, Chile, Paraguay and Bolivia.
Operation Condor was secretly launched in the 1970s.
Judges at the court in Buenos Aires announced the sentencing of Bignone, Argentina’s last dictator, on Friday.
Former Uruguayan Col Manuel Cordero – the only non-Argentine defendant – was jailed for 25 years.
The judges are continuing to deliberate the sentencing of the rest of the former military officers.
Since the trial started in 2013, five defendants, including Jorge Rafael Videla, the head of Argentina’s junta during its first three years, have died.
Operation Condor – named after the largest vulture in South America – began in 1975 at a meeting of intelligence chiefs from Argentina, Bolivia, Chile, Paraguay and Uruguay.
It later came to include Brazil, and – in a more peripheral role – Ecuador and Peru.
The operation, which continued in the 1980s, brought together the military of neighbouring nations that had previously been at war with each other in order to fight a new common enemy – the spread of Marxist ideology throughout the region.