A court in Argentina has cancelled pardons for human rights violations granted to two former military leaders, Jorge Videla and Eduardo Massera.
A military junta led by Gen Videla seized power in Argentina in 1976
The court said the pardons granted in 1990 by former Argentine President Carlos Menem were unconstitutional.
The two men were originally sentenced to life imprisonment in 1985 for the abuses committed by the military governments between 1976 and 1983.
The former president and navy chief could now be sent back to prison.
Gen Videla has been under house arrest for years for his alleged involvement in the abduction of children.
Admiral Massera is also under house arrest for the kidnappings, but after suffering a stroke in 2002 he won a court ruling that he was mentally unfit to stand trial.
Battle for justice
A military junta led by Gen Videla seized power in Argentina in 1976.
Under its rule, a so-called "dirty war" was waged against left-wing opponents, whom the military accused of terrorism.
Human rights groups say between 10,000 and 30,000 people were killed or disappeared before Argentina returned to civilian rule with the election of President Raul Alfonsin in 1983.
In 1985, Gen Videla was tried and convicted for the murder of 66 people, the torture of 93 others, and the illegal detention of more than 300.
Adm Massera was found guilty of three murders, the torture of 12 people, and the detention of 69 others.
However, in 1990 President Menem pardoned the military leaders in order to "close a sad and black stage of Argentine history".
Condemned at the time, the pardons have been challenged by the present government of President Nestor Kirchner.
The BBC's Daniel Schweimler in Buenos Aires says that when democracy returned to Argentina, the military still had a powerful influence and many simply wanted to forget the past.
But a small group maintained the battle for justice and now, according to our correspondent, it seems their efforts are finally paying off.