Hundreds of thousands of Brazilians poured onto the streets of major cities on Sunday to protest against President Dilma Rousseff, deepening a political crisis that threatens to unseat the leftist leader amid the worst recession in a generation.
The demonstrations were the latest in a wave of anti-government rallies that lost momentum late last year but have again gained strength as a sweeping corruption investigation nears Rousseff's inner circle.
From the Amazon jungle city of Manaus to the business hub of Sao Paulo and the capital Brasilia, protesters marched in a nationwide call for Rousseff's removal, raising pressure on lawmakers to back ongoing impeachment proceedings against her in Congress.
No official estimates for the number of protesters across Brazil were immediately available. But two government sources, speaking on condition of anonymity, told Reuters the demonstrations could be bigger than anti-government rallies in March 2015, which gathered as many as 1 million people.
In a preliminary tally, polling firm Datafolha estimated 450,000 demonstrators in Sao Paulo on Sunday, the biggest rally in the city's history and more than twice the size of a previous protest a year ago.
In the skycraper-lined Avenue Paulista in Sao Paulo, a sea of protesters wearing the national yellow-and-green colors chanted "Dilma out" and waved banners that read "Stop the corruption."
"I support her impeachment and new elections because the presidential vote in 2014 was financed with dirty money from corruption," said Alexandre Cortes, a 39-year-old engineer draped in a Brazilian flag at the festive rally in Sao Paulo.
Many blame Rousseff for sinking the economy into its worst recession in at least 25 years. Opinion polls show that more than half of Brazilians favor the impeachment of the president, who was re-elected for a second four-year term in 2014.
Rousseff is the latest leftist leader in Latin America to face social upheaval as a decade-long commodities boom that fueled breakneck growth rates comes to an abrupt end.
Ahead of the demonstrations, tensions were high after Sao Paulo state prosecutors requested the arrest of Rousseff's predecessor and political mentor, Luiz Inacio Lula da Silva, on money-laundering charges. A judge still has to decide on the request, which can be rejected.
As in previous protests, Sunday's rallies were led by middle-class Brazilians angry over growing allegations of corruption in Rousseff's administration. No violence was reported.
Poor Brazilians, who form the traditional base of the ruling Workers' Party, have not turned out in great numbers in recent protests. But their support for Rousseff has faded as unemployment rises and inflation climbs.
"This government helped many people buy homes, cars and electronics, but we still don't have health, education and basic sewage," said Paulo Santos, a waiter who stopped at the beach-front demonstration in Rio de Janeiro before heading to work.
In the capital, Brasilia, protesters inflated a giant doll of Lula wearing a striped prison uniform and chained to a ball that read "Operation Carwash," the name of the investigation centered on state oil company Petrobras (PETR4.SA). Police estimated about 100,000 protesters in Brasilia, but that figure could not be independently confirmed.
Speaking to protesters in the city of Belo Horizonte, the leader of the opposition PSDB party, Aecio Neves, said Rousseff should not remain in office.
"We believe that the president is no longer capable of making Brazil return to growth," said Neves who narrowly lost the 2014 election to Rousseff and has called for new polls. "With the strength of our people, we will build a better future for Brazil."
For Brasilia-based political analyst Leonardo Barreto, the massive scale of Sunday's demonstration could accelerate impeachment hearings in Congress.
"Today's protests give legitimacy to this process," Barreto said. "If the government fails to react, the impeachment process will move faster."
The two-year-old corruption probe has already strained Rousseff's ties with her main coalition partner, the Brazilian Democratic Movement Party (PMDB). At its national convention on Saturday, the PMDB said it would decide within a month whether to break with the government, with party insiders saying the mood of the country would be decisive.
Small groups of government supporters wearing red shirts and holding banners that read "There will not be a coup" marched in several cities.
The Petrobras probe has implicated senior politicians from Rousseff's coalition as well as top business executives.
Popular discontent grew in recent weeks after a ruling party lawmaker reportedly testified under a plea bargain and accused Rousseff and Lula of trying to hamper the Petrobras investigation.
Protesters also voiced support for Sergio Moro, the judge overseeing the Petrobras investigation, holding banners that read "We are all Moro" and wearing masks of his face.
Shares in Brazilian companies and Brazil's real currency BRL= have surged in recent weeks as investors bet that a change in government would lift business and consumer confidence and rescue an economy that contracted 3.8 percent last year.
Rousseff, whose popularity is near record lows, has said she will not quit and blamed her opponents for creating the crisis that is sinking the economy.
Political tensions have stalled Rousseff's legislative agenda, which included measures to limit public spending and overhaul a costly pension system to regain investors' trust.