Human rights activist Adolfo Pérez Esquivel, recipient of the 1980 Nobel Peace Prize, was taken to hospital following a health scare, a rights group he founded said on Sunday.
The 90-year-old was taken to a hospital in the seaside resort of Mar del Plata as rumours circulated that he had suffered a stroke.
"The CAT scan came out well. The doctors rule out a stroke. They will perform an MRI (magnetic resonance imaging)," the Servicio de Paz y Justicia (Peace and Justice Service, SERPAJ) said on social media, referring to Pérez Esquivel's hospitalisation at the tourist resort of Mar del Plata.
An architect, sculptor, painter and activist for humanitarian causes, Perez Esquivel was awarded the Nobel Prize for his defence of human rights and democracy in the face of Argentina's last military dictatorship from 1976 to 1983. He was himself detained and tortured by the military rulers.
"Adolfo slept well. They took his blood pressure, measured his glucose and gave him medication. He is stable. He will remain under observation for 24 hours to see how he evolves," said SERPAJ.
Initial reports suggested he had suffered a stroke. The SERPAJ dismissed those claims and promised to give more reports on his evolution.
Born in a the Buenos Aires neighbourhood of San Telmo, Pérez Esquivel had since his youth campaigned against violence and in favour of the most marginalised in society.
He spent 14 months in prison and another 14 months under probation. It was during this time that he was awarded the Nobel Prize, a fact that caused bewilderment and irritation among the regime's generals, who were condemned years later for their systematic plan to eliminate and disappear opponents.
"Institutionalised violence, misery and oppression enshrine a social order that benefits a few: the rich getting richer at the expense of the poor getting poorer," he said on receiving the Nobel in 1980.
Pérez Esquivel is the son of a Spanish immigrant father from Galicia and a mother of indigenous origin from the province of Corrientes. He is a self-professed admirer of Mahatma Ghandi and Martin Luther King.
In addition to his imprisonment, there was also an assassination attempt against his life during the dictatorship era.
"Two days after the Nobel Prize was announced, we were on our way with my son Leonardo to SERPAJ, and some people came forward with guns in their hands to kill us. My son accelerated the car and luckily there was a taxi that intervened and saved our lives," he said.
In a recent interview he condemned the worldwide growth of the far-right: "It is worrying. They are totalitarian movements or philo-Nazi groups. It has to do first of all with a lack of memory."
Pérez Esquivel is one of five Argentines to have received a Nobel Prize.