Thousands of people marched in Buenos Aires on Friday to condemn violence against women, the latest public outcry following the recent killings of three 12-year-old girls in Argentina and the gang rape of a teenage girl in Brazil.

The rally was organized on social media by women's groups under the slogan #NiUnaMenos, meaning "Not one less." Demonstrators wearing the purple wigs that represent the movement flooded the streets in front of the congress building. Many waved flags or wore shirts emblazoned with photos of victims of domestic violence.

"We're here because we want justice. Not just for us but everyone who has suffered," said Angelica Itati Nunez. She held a T-shirt displaying photos of her 15-year-old daughter, six-year-old granddaughter and her mother-in-law, who were killed by the same man in 2012.

There were 275 gender-based killings of Argentine women in the past year, according to Casa del Encuentro, a women's rights group and shelter. In 40 of those cases, women had reported attacks by men, and some even had a restraining order.

Angelica Itati Nunez, centre, cries as she holds a picture of her relatives who were killed by a man in 2012. She marched on Friday with thousands of people against domestic violence outside the National Congress in Buenos Aires. (Victor R. Caivano/Associated Press)

In the case of Karina Abregu, half her body was badly burned after her husband doused her with alcohol and set her on fire in 2014. She had already reported beatings and other abuses during their 13 years of marriage, but she said authorities failed to intervene. Her husband was only jailed after her case was reported in the press.

"If we don't get the protection we need from the government, we'll keep fighting in the streets to get it," said Abregu, whose husband was sentenced last April to 11 years in prison.

The #NiUnaMenos movement was launched in Argentina last year and garnered global attention. Argentine soccer star Lionel Messi joined last year's campaign with a message against femicides published on his Twitter account.

During a recent visit, U.S. First Lady Michelle Obama also praised the efforts by Argentine women to fight against violence.

A woman holds up a sign with the shape of a woman's body during a demonstration to demand policies to prevent femicides. (Marcos Brindicci /Reuters)

This year's march comes after the recent killings of three 12-year-olds in Argentina. Micaela Ortega was found strangled on the outskirts of Buenos Aires. Police say a 26-year-old man tricked her into meeting him by pretending to be a girl of her same age using a fake profile on Facebook. Authorities say Milagros Torres was strangled by her mother's former boyfriend in northern Argentina. Guadalupe Medina was abused and murdered by a drug gang in Santa Fe province.

Similar marches against gender-based violence were held Friday in Uruguay and Brazil, where the recent gang rape of a 16-year-old girl was posted online, shocking the nation and highlighting its endemic problem of violence against women