By a margin of 16 to 15, the Senate voted late Tuesday to overturn the measure, known as the Expiry Law.  The bill now goes to the lower house for minor changes.  Lawmakers spent more than 12 hours debating the bill before putting it to a vote.

The amnesty measure was passed in December 1986 to pardon human rights violations during the 12-year dictatorship.  The measure has protected most uniformed officials ever since and past efforts to overturn it have failed.

Amnesty International has in the past called for the law to be annulled.  The human rights group has said the law violates Uruguay's international legal obligation to provide justice and uncover the difficult truths of its recent past.

In March of last year, a court sentenced former President Juan Maria Bordaberry to 30 years in prison for rights violations stemming from the dictatorship.

Bordaberry was elected president in 1971.  In 1973, he dissolved Congress and began a repressive campaign against dissidents.  The former dictator was pushed out of power by the military in 1976.

In October 2009, a court sentenced former dictator Gregorio Alvarez to 25 years in prison for murder and human rights violations committed while he held power from 1981 to 1985.