BUENOS AIRES, Argentina – A court sentenced one of Argentina's most feared former military leaders to life in prison on Thursday for the 1977 kidnapping, torture and killing of four leftist activists.

Luciano Benjamin Menendez, 81, was commander of the regional Third Army Corps in Cordoba for five years during Argentina's 1976-83 military dictatorship and controlled one of the regime's most notorious torture centers.

Hours before the sentencing, an unrepentant Menendez read a statement in front of television cameras in the courtroom saying the regime's repression had been justified in the face of a leftist militant threat.

“We had to take appropriate measures,” he said, enraging activists one of whom screamed “genocide” and had to be removed from the courtroom.

Menendez, who was already under house arrest for previous “dirty war” convictions, will be transferred to a prison following Thursday's conviction and sentencing.

Hundreds of people gathered outside the courtroom – many holding placards and pictures of the alleged victims – erupted into cheers upon hearing the verdict, which was read on local television stations.

The verdict was considered important both because of Menendez's gruesome reputation and because he was ordered to serve the rest of his sentence in prison.

Many convicted former military officers are serving their sentences under house arrest, as allowed by an Argentine law that applies to those over 70 years old or of poor health. A court can choose to send them to prison anyway, however, as was the case with Menendez.

Six other former military officers and one civilian were also convicted Thursday in connection with the killings of the activists and given sentences ranging from life in prison to 18 years. The trial lasted less than two months.

The four victims, Hilda Palacios, Humberto Brandalisis, Carlos Lajas and Raul Cardozo, were kidnapped in 1977. They were members of the Revolutionary Workers Party.

According to prosecutors, the four were taken to the prison and torture center known as La Perla, which was run by the Third Army Corps, and killed within a month. Their bodies were then dropped in the street to make it seem as if they had been killed in a shootout, before being picked up by authorities.

Palacios' body was found in 2004 in a local cemetery. The bodies of the others have not been found.

Menendez's is the latest conviction of a “dirty war” suspect. Seven ex-military officers and a former police official were convicted of human rights abuses in December. Also, a top ex-navy chief was charged earlier this month in the 1977 kidnapping and murder of a prominent journalist.

President Cristina Fernandez has made advancing human rights trials a priority since taking office. In 2005, the Supreme Court struck down amnesty laws from the 1980s that had protected suspects from the dictatorship.

About 13,000 people were killed during the dictatorship, according to official numbers, but human rights groups claim the number is closer to 30,000.