The human rights activist Lidia “Taty” Almeida – who spent more than half a century searching for her son after he was forcibly disappeared by Argentina’s military junta – has died aged 95, prompting a public outpouring of grief.

Almeida, 95, was the president of the Mothers of Plaza de Mayo, made up of women who have marched around the square outside Argentina’s presidential palace every Thursday since 1977, demanding the return of children who were disappeared during the country’s 1976-1983 dictatorship.

Almeida’s son Alejandro was kidnapped by anti-communist paramilitaries in June 1975, nine months before the coup in which a military junta seized power. For five decades, Almeida searched for the truth about his fate.

Alejandro has never been found, but Almeida became a figure of moral authority and an emblem of the enduring fight for justice. She appeared in public to demand justice for the dictatorship’s atrocities, as well as campaigning on contemporary social justice issues, even in the final year of her life.

Her family said she died surrounded by loved ones late on Sunday at a hospital in Buenos Aires. The Mothers of Plaza de Mayo said she had continued her work until she fell ill in recent days.

“Thank you for teaching us that to love is to resist, that the only fight we lose is the fight we give up, and that there is no force greater than that of love,” the Mothers of Plaza de Mayo Founding Line wrote in a tribute to Almeida on Sunday night.

Almeida was born Lidia Stella Mercedes Miy Uranga on 28 June 1930 in Buenos Aires. She had three children with her husband, Jorge Almeida, and worked as a teacher before dedicating herself to raising her family.

Her father was a cavalry officer, and when Alejandro was forcibly disappeared in 1975, her first instinct was to turn to military contacts for help. But as she learned the truth about the dictatorship’s atrocities and met other mothers who were searching for adult children who had been forcibly disappeared, her life transformed and she became an emblem of the fight against state terror.

Alejandro was a medical student at the University of Buenos Aires and a member of the People’s Revolutionary Army, a Marxist-Leninist guerrilla group. He was also a poet, and in 2008 Almeida published a collection of his poetry that she had found in one of his diaries after he was kidnapped.

In 2024, Almeida became the president of the Mothers of Plaza de Mayo Founding Line (the group split into two in the 1980s due to political differences).

Major figures in Argentinian public life have paid tribute to her. Former President Cristina Fernández de Kirchner described her as an “indefatigable fighter who honoured life”.