Former Army Gen. Luciano Menendez attends his trial in Cordoba, Argentina, in 2010. (Natacha Pisarenko/ASSOCIATED PRESS)

Luciano Menéndez, a former Argentine general convicted of his role in the killings and forced disappearances of political adversaries under the military junta that ruled from 1976 to 1983, died Feb. 27 in a military hospital in the city of Cordoba. He was 90.

Argentine media reported the death and said he had been hospitalized for coronary and biliary conditions.

Mr. Menéndez, who was born into a military family, was one of the most bloodthirsty leaders of a violent dictatorship. Government death squads and paramilitary forces did their utmost best to eradicate armed leftist groups as well as political rivals and others they came to suspect of being dissidents, including artists, authors, academics, social workers, labor unionists and journalists.

Under the junta, between 13,000 and 30,000 people “disappeared,” and were tortured and killed, according to human rights groups. Victims were buried in mass graves or drugged, then thrown out of airplanes over large bodies of water. Another tactic was the kidnapping of children of suspected radicals; the prisoners were killed and the babies were handed over to childless military families. An estimated 500 children of the disappeared were born in detention.

During this period, which came to be known as the “dirty war,” Mr. Menéndez was the head of the Third Army Corps, commanding 10 Argentine provinces and overseeing the largest detention center, La Perla, in Cordoba, which one witness called “a factory of death.”

Former Gen. Luciano Menendez, right, talks with his attorney Horacio Guerineau at a courthouse in San Miguel de Tucuman, northern Argentina, in 2008. (Julio Pantoja/ASSOCIATED PRESS)

Mr. Menéndez presented himself as a Cold Warrior who saw himself as a bulwark against communism, at all costs. “We are going to have to kill 50,000 people: 25,000 subversives, 20,000 sympathizers, and we will make 5,000 mistakes,” he was widely quoted as telling his men.

At La Perla, all officers participated in torturing and executing prisoners as part of a “blood pact,” sharing responsibility for the actions, said Marguerite Feitlowitz, who has interviewed former prisoners and is the author of the book “A Lexicon of Terror: Argentina and the Legacies of Torture.”

“They all have to participate in these acts: kidnapping, torture assassination, murder,” Feitlowitz said. “This becomes like shared blood among them.”

Mr. Menéndez laughed during torture sessions, earning the nickname the “Hyena,” according to the Agence France-Presse. He later defended his brutal actions as necessary measures to prevent leftist guerrillas from obtaining power. “These were not peaceful citizens,” he said in 2010, according to the Associated Press.

In 2016, Mr. Menéndez was convicted of 52 homicides, 260 kidnappings, 656 torture cases and 82 disappearances of people who were never found, the AFP reported at the time. At his trial, he said there was “never repression of any kind” at La Perla. “These criminals accuse the armed forces and go to the courts saying they’re victims.”

Over the past two decades, since Argentina’s high court cleared the way, Mr. Menéndez and higher-ranking leaders including Jorge Rafael Videla, an army commander who was president from 1976 to 1981, faced convictions for the crimes committed under the junta.

Mr. Menéndez was given 14 prison terms and 12 life sentences, more than any other military leader of the dictatorship, according to the Spanish-language news agency EFE.

Luciano Benjamín Menéndez was born June 19, 1927, in San Martin, a suburb of Buenos Aires. He was a nephew of Gen. Benjamín Menéndez, who tried unsuccessfully to overthrow President Juan Domingo Perón in 1951, and a cousin of Gen. Mario Menéndez, who became the military governor of the Falkland Islands while Argentina briefly occupied the archipelago in 1982.

His wife, Edith Angélica Abarca, died in 2012. A complete list of survivors was not immediately available.

Amid increased international attention to human rights violations in Argentina, many leaders attempted to pay at least lip service to toning down extrajudicial killings. Mr. Menéndez was the exception.

He accused Roberto Viola, commander in chief of the army, of “inadmissible tolerance” toward “Marxist subversion” and led a brief and failed insurrection to oust him in 1979, The Washington Post reported in 1979. As a result, Mr. Menéndez was imprisoned for 90 days and forced into retirement.

After the Falklands debacle, the regime crumbled, and Argentina returned to democracy. Over the next years, he was called to testify about his involvement in human rights crimes. At one hearing in 1984, he was seen being restrained by aides after he drew his parachutist’s knife in response to protesters taunting him; he claimed that he was protecting his wife and daughter against “another attack on the armed forces” by leftist sympathizers. A photo of the incident came to be seen as emblematic of his brutish temperament.

In a controversial move, President Carlos Menem in 1990 pardoned military leaders, including Mr. Menéndez, as well as left-wing guerrilla leaders in what he called a gesture of national healing. In 2005, Argentina’s supreme court struck down those amnesty laws under left-leaning, populist president Nestor Kirchner. Mr. Menéndez was also stripped of his military rank.

Three years later, Mr. Menéndez was given the first of his life sentences. He defended himself in court.

“Argentina flaunts the dubious merit of being the first country in history to judge its victorious soldiers,” he said. “They call the operations of the armed forces illegal repression.”