Police in Spain have arrested Argentine ex-President Isabel Peron over the 1976 disappearance of a leftist activist.
Isabel Peron has been living in Spain since 1981
An Argentine judge on Thursday issued a warrant for her arrest, in connection with a right-wing paramilitary group active during her time in office.
Mrs Peron has since been released from custody. Argentina now has 40 days in which to file an extradition request, a court statement said.
The Spanish judge said she would have to report to the police every 15 days.
Mrs Peron is the third wife of ex-President Juan Domingo Peron. She took over from him when he died in 1974.
The Argentine authorities are investigating the activities of a death squad, known as Triple A, that is accused of killing left-wing opponents on government orders in the 1970s.
Argentina was wracked by violence and killings in the period after Mrs Peron came to power.
She was removed by a military coup in 1976, and has been living in Spain since 1981.
A judicial source told Reuters news agency that Mrs Peron may be able to fight extradition on the basis of her dual Argentine and Spanish citizenship.
The judge, Raul Acosta, alleges that the disappearance of the activist, Hector Aldo Fagetti Gallego, was in effect authorised by her signature of three decrees allowing Argentina's armed forces to take action against "subversives".