MEXICO CITY (AP) ― Juan Gelman, a renowned Argentine poet and left-wing activist who was awarded the prestigious Cervantes Prize, has died in Mexico. He was 83.

Argentine President Cristina Fernandez on Wednesday announced three days of mourning in his native country, where writers paid homage to him as one of the most brilliant writers in Spanish of the 20th century.

“Gelman worked with words like they were plastic, he modeled them,” writer Vicente Muleiro told reporters.

He was widely mourned as well in Mexico, where he lived for more than 20 years before his death Tuesday of undisclosed causes.

“Juan Gelman, poet of the Mexican soul, major poet, has died. My condolences to his loved ones,” Mexico’s National Culture and Arts Council President Rafael Tovar y de Teresa said via Twitter.

Gelman’s life and work were deeply affected by personal loss suffered during Argentina’s 1976-1983 military dictatorship. Government forces kidnapped and killed his son and daughter-in-law, among tens of thousands of suspected leftists who were “disappeared” across Latin America in that era.

“I died many times, and with each report of a murdered or disappeared friend, the pain of those lost became greater,” he said during his acceptance speech of the Cervantes prize in 2008.

“The wounds are not closed yet. They lie just below the surface of society like a relentless cancer.”

He was tall and wispy and spoke in a soft, raspy voice. He lived in a roomy, well-lit apartment stacked with book shelves in the Mexico City neighborhood of La Condesa. He received numerous awards including the Juan Rulfo prize in 2000 and in 2005 the Reina Sofia poetry award and the Pablo Neruda Iberoamerican poetry prize.

The son of a Russian leftist who became disillusioned with Joseph Stalin’s regime, Gelman was born in 1930 and grew up in a predominantly Jewish neighborhood of Buenos Aires.

He joined the Communist Youth Federation at 15, but left the party in the 1960s to become part of a group that would later evolve into the Montoneros guerrilla group, which he also quit in 1979 in opposition to its militarism.

Up until then, he published the poetry volumes “Gotan” (1962) and “Colera buey” (1962-1968).

Gelman was abroad at the time of the 1976 coup, but his 20-year-old son Marcelo and 19-year-old daughter-in-law Maria, who at the time was seven months pregnant, were seized. He never found Maria’s remains, but in 1990 he was able to identify his son’s.

For years, he tried to track down his granddaughter, who was adopted after her parents were killed in prison, and finally found her in neighboring Uruguay in 2000. After learning she was related to the poet, she changed her last name to Gelman.