Argentina's lower House of Congress has voted overwhelmingly to annul a pair of 1980s laws that granted amnesty to members of the former military regime accused of human rights abuses.
Tuesday's vote followed seven hours of debate on the matter, which now goes to the Senate for consideration.
Rights group said up to 30,000 people, mostly leftists and opponents of the military regime, were killed during the 1976 to 1983 dictatorship.
Amnesty laws passed in the 1980s allowed many of those responsible to avoid prosecution.
Last month, Argentine President Nestor Kirchner annulled a decree that blocked the extradition of military officials and others suspected of atrocities during the dictatorship.