Brazilian police say some 3 million people across the country took to the streets Sunday demanding the ouster of President Dilma Rousseff.
Protesters urged lawmakers to continue with ongoing impeachment proceedings against the president who finds herself embroiled in a corruption scandal and presiding over the country's worst recession in 25 years.
Sergio Praca, a political analyst at the Getulio Vargas Foundation in Rio de Janeiro said the demonstrations "were very powerful" and were "the worst scenario possible for the government."
Rousseff and her Workers' Party are struggling to hold on to power as officials delve into a probe of massive corruption at state oil company Petrobras.
Prosecutors say more than $2 billion was paid in bribes and other funds by the nation's biggest construction and engineering firms in exchange for inflated Petrobras contracts.
Dozens of former Petrobras executives and political figures, including Rousseff's predecessor and mentor, former president Luiz Inacio Lula da Silva, are under investigation. Some of the alleged wrongdoing took place while Rousseff was chairman of the Petrobras board.
Rousseff and her party are also facing a new threat. On Saturday, the Workers' Party main coalition partner, the Brazilian Democratic Movement Party, said it will decide in 30 days whether it will maintain its alliance with the Workers' Party.