Santiago, Chile - Chileans elected former student leader Gabriel Boric as the country's youngest ever president on Sunday.

The 35-year-old was facing right-wing politician Jose Antonio Kast in a run-off vote for the country's highest office.

With 99% of the vote counted, Boric received 55.9% of the vote, while Kast took 44.1%.

Kast said on Twitter he had spoken to his rival and congratulated him on "his great triumph."

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"From today he is the elected President of Chile," Kast wrote on the social media site.

A total of around 15 million people are eligible to vote in the South American country.

Boric has promised public education, better health care and champions the rights of migrants, indigenous people, and LGBTQ+ people.

Kast – a father of nine and a devout Catholic – promised tax cuts, a border wall against illegal immigration, and a firm hand against criminals. He is a notorious sympathizer of former right-wing dictator Augusto Pinochet, who was installed after a US-backed coup in 1973.

During the election campaign, Kast said: "If Pinochet were still alive, he would vote for me."

Chile still has the highest per capita income in South America. Poverty has been significantly reduced in recent decades, but the nation has been suffering from growing social inequality. Large parts of the health and education systems have been privatized, and more and more people feel left behind.

Two years ago, thousands took to the streets every day for weeks to demand social reforms and the resignation of President Sebastian Pinera.