Amnesty International has welcomed the sentence handed to a former Argentine president responsible for crimes against humanity in the 1970s and 80s.
Jorge Videla, a former military general, was found guilty of killing dissidents during the country's "Dirty War" - a period of military rule between 1976 and 1983.
The 85-year-old, who was the de facto president of Argentina between 1976 and 1981 after becoming the first leader of the military junta, was ruled "criminally responsible" for the torture and deaths of 31 prisoners in Córdoba.
Twenty-two other officers were also found guilty for the murders by a court in the city of Córdoba on Wednesday. Among them was General Luciano Benjamín Menendez, who was also sentenced to life in prison.
"This judgement represents another important step in the fight against impunity. Finally those responsible for the grave human rights abuses committed under past military regimes are being brought to justice," said Guadalupe Marengo, Amnesty International's Americas Deputy Director.
Videla was already serving a life jail term for abuses committed during the "Dirty War".
A new arrest warrant was issued against Videla in 2008 for his alleged involvement in hundreds of cases of enforced disappearances, torture and extrajudicial executions.
The judges in Cordoba ruled that he must serve a life sentence for the murder of the 31 left-wing activists, who were shot dead shortly after the military took power.
During Argentina’s military government thousands of people were forcibly disappeared, unlawfully executed and tortured.
The amnesty laws in Argentina that had protected the security forces from prosecution were declared null and void in June 2005, two decades after having been introduced by the government of President Raúl Alfonsín in 1986-87.
According to official data, by the end of this year, 110 people had been convicted for their role in human rights violations committed under the military regimes of the past. Another 820 were facing criminal charges and 13 trials were continuing.
Despite progress in bringing to justice perpetrators of past human rights violations, a report by the Supreme Court admitted that there had been some delays, particularly in provincial courts.
"It is encouraging that Argentina is taking steps in the right direction to end impunity for past human rights violations. The pursuit of justice for victims and their relatives must continue without delay, and with the necessary resources to ensure that impunity is brought to an end," said Guadalupe Marengo.