Col Cordero fought extradition to Argentina
Brazil has extradited to Argentina a former army colonel charged there with human rights abuses dating back to military rule during the 1970s.
Col Manuel Cordero Piacentini is accused of taking part in the notorious Operation Condor.
This was the plan supported by several South American military rulers to liquidate opponents.
The Uruguayan-born officer, who was arrested in Brazil two years ago, faces charges of kidnapping and murder.
Col Cordero, who served as an intelligence officer in the Uruguayan army, was allegedly involved in the disappearance of an Argentine citizen.
His extradition was ordered on Tuesday but had been postponed as his lawyers argued his health was so poor he should remain in hospital, AFP reported.
However, following medical examinations, Col Cordero was driven by ambulance to the Brazilian border where he was handed over to the Argentine police.
He had unsuccessfully attempted to avoid extradition by insisting he was protected under a Brazilian law that grants amnesty to Brazilian soldiers who were acting under that country's military government.
Such an amnesty does not exist in Argentina.