A former general who ran a detention centre during Argentina's military dictatorship has been sentenced to life in prison for human rights violations.

Santiago Omar Riveros was commander of the notorious Campo de Mayo prison near Buenos Aires where an estimated 5,000 prisoners were held during the 1976-83 dictatorship.

Santiago Omar Riveros was found guilty on Thursday of torturing and beating to death Floreal Avellaneda, a 15 year old boy, and of abducting his mother Iris.

The two were abducted one month after the 1976 military coup, in order to find out the whereabouts of Floreal Avellaneda's father, a Communist Party Union leader of the same name.

Iris was released after nearly three years of detention and torture; her son's body was found washed up on the Uruguayan coast, bound by the hands and feet, and with signs of beating.

"This sentence is an important achievement in the fight for justice for the victims of Argentina's 'dirty war' and the struggle against impunity enjoyed by so many of the perpetrators," said Javier Zuniga, Amnesty International's special adviser.

The teenager's father said he was satisfied with the verdict, but called for Santiago Omar Riveros to receive no clemency."The sentence must be served in a common prison. Even if he dies in prison, he will never suffer what we suffered," he said.

The former general, who is now 86, is accused of more than 40 crimes against humanity involving victims of the era's so-called "disappeared". During the years of military rule, headed by General Leopoldo Galtieri, around 30,000 people vanished at the hands of the security forces and are still unaccounted for.