Luiz Inacio Lula da Silva was sworn in as Brazil's president on Sunday, delivering a searing indictment of far-right former leader Jair Bolsonaro and vowing a drastic change of course to rescue a nation plagued with hunger, poverty and racism.

In a speech to Congress after officially taking the reins of Latin America's biggest country, the leftist said democracy was the true winner of the October presidential vote, when he ousted Bolsonaro in the most fraught election for a generation.

Bolsonaro, who left Brazil for the United States on Friday after refusing to concede defeat, rattled the cages of Brazil's young democracy with baseless claims of electoral weaknesses that birthed a violent movement of election deniers.