In pictures: Jorge Rafael Videla

Undated file photograph showing former Argentine dictator Jorge Rafael Videla in Buenos Aires. AFP

Argentina's former military leader Jorge Rafael Videla has died aged 87 while serving a sentence for crimes against humanity.

Former Argentine dictator and general, Rafael Videla, is seen during his trial to investigate the crimes committed during Operation Condor, a campaign established by Argentina, Chile, Paraguay, Brazil, Bolivia and Uruguay's dictatorships to quash the opposition during the 1970s, in Buenos Aires on March 5, 2013.

He is said to have died of natural causes in prison.

Two army soldiers read a newspaper in the Buenos Aires Plaza de Mayo March 24, 1976 after a military coup led by Gen Jorge Rafael Videla ousted President Isabel Peron.

A military junta under Videla seized power from the Peronist party in 1976.

General Orlando Ramon Agosti (R) and Admiral Emilio Massera (L) stand as Lieutenant General Jorge Rafael Videla (C), President of Argentina, takes an oath as 38th president of the Argentine Republic, 29 March 1976, in Buenos Aires.

Parliament was dissolved and opponents of the regime were rounded up in the 'Dirty War', which saw thousands of people 'disappear'.

Jorge Rafael Videla (L) presents the World Cup trophy to Argentine national soccer team captain Daniel Passarella after the Argentine vs Netherlands match on June 25, 1978

Here Videla is seen presenting the World Cup trophy to national football team captain Daniel Passarella after Argentina beat the Netherlands in the final on 25 June 1978.

Former Argentine military leader Gen Jorge Rafael Videla takes communion from a priest of a local church, Buenos Aires, 30 December 1990. a day after he was released from prison

Gen Videla was sentenced to life in prison for torture, murder and other crimes in 1985, but pardoned in 1990 under an amnesty given by the president at the time, Carlos Menem.

Demonstrators hold a figure representing Jorge Videla grabbing a street sign in Buenos Aires, 24 March 2006

But then in April 2010, the Supreme Court upheld a 2007 federal court move to overturn his pardon.

A demonstrator holds a placard with the portrait of Videla and the inscription "Honduras-Never Again In The Big Motherland" during a protest against the coup d'etat in Buenos Aires, on July 2, 2009.

He was jailed eight months later for the deaths of 31 dissidents during the dictatorship, of which he was overall leader until 1981.

Former dictators Jorge Rafael Videla, second from right, and Reynaldo Bignone, right, wait to listen the verdict of Argentina's historic stolen babies trial in Buenos Aires, Argentina, Thursday, July 5, 2012. (AP Photo/Natacha Pisarenko)

In 2012, he was also convicted of overseeing the systematic theft of babies from political prisoners. A court in Buenos Aires sentenced him to 50 years in prison, while another ex-military leader, Reynaldo Bignone, received 15 years for his alleged role in the crime.