Mexican President Claudia Sheinbaum offered an official apology Wednesday for the massacre of students by the army in 1968, in one of her first acts after taking office.
"October 2nd will not be forgotten!" Sheinbaum, a former student activist who calls herself the "daughter of '68," declared on the anniversary of the massacre.
According to official figures, 30 people died when security forces opened fire at students holding a peaceful rally in the Tlatelolco district of Mexico City days before the country hosted the Olympic Games.
Relatives and activists say that around 400 people died.
Giving her first news conference after being sworn in Tuesday as Mexico's first woman president, Sheinbaum said that a decree would be issued describing the killings as a crime against humanity.
Never again would the security forces be used "to attack or repress the people of Mexico," she promised, hours before a planned protest in Mexico City to demand justice for the victims of the massacre.
Sheinbaum was born to Bulgarian and Lithuanian Jewish migrants in Mexico City during the turmoil of the early 1960s, when students and other activists were seeking to end the Institutional Revolutionary Party's long grip on power.
Her mother lost her job as a university professor for denouncing the massacre.
Hours after Sheinbaum's remarks, thousands of people took part in a traditional annual demonstration in memory of the fallen students.
Some protesters, known as the "black bloc" because of their black hooded clothing, threw stones and firecrackers at police officers guarding the Zocalo, Mexico City's main square and home to the presidential palace.
"It is not enough to apologize. We want justice... You can give apologies to your friends, but not to us who gave our lives to change this country," said Oscar Menendez, 90, who was present at the 1968 tragedy.
Angel Rodriguez, 76, who also took part in the student movement, said the apology goes some way in improving the relationship between people and the state.
"She was not obliged to offer that apology. It should have been previous presidents, immediately after the massacre," Rodriguez said.
Sheinbaum, a scientist by training, won a landslide victory in June elections with a vow to continue the left-wing reform agenda of her predecessor Andres Manuel Lopez Obrador, a close ally.
Lopez Obrador left office this week after six years due to the country's single-term limit, despite an approval rating of around 70 percent, largely thanks to his policies aimed at helping poorer Mexicans.
Sheinbaum takes the reins of a nation where criminal violence, much of it linked to drug trafficking and gangs, has claimed more than 450,000 lives since 2006 -- an issue she will address when she presents her security plan next week.
