Mammoth demonstrations across Brazil are putting even more pressure on embattled President Dilma Rousseff as she heads into a tough week for her attempt to survive impeachment proceedings in Congress.
According to police estimates, a total of 3 million people took to the streets in 200 cities on Sunday calling on the president to resign amid widespread anger over corruption investigations and the worst recession in years.
Sometime this week, lower house Speaker Eduardo Cunha, a Rousseff foe, is expected to form a commission to begin impeachment proceedings over allegations of fiscal mismanagement. He doesn't have any say on the panel's membership, but on Saturday members of his centrist PMDB party pledged to be more independent from Rousseff's administration.
Rousseff, who has said she won't resign, is also under pressure from members of her own Workers' Party, whose leaders want her predecessor and mentor Lula da Silva to intervene by taking a Cabinet post and bringing in others of his choice. Yet Silva is awaiting a decision by a Sao Paulo judge on whether he will be detained on corruption charges.
Sunday's protests add to the already-difficult position of Rousseff, who in addition to the impeachment effort is faced with a sprawling investigation by federal prosecutors into corruption at state-run oil giant Petrobras that has moved closer to her inner circle in recent weeks.
In a statement after Sunday's protests, Rousseff said, ''The peaceful character of this Sunday's demonstrations shows the maturity of a country that knows how to co-exist with different opinions and knows how to secure respect to its laws and institutions.''
The biggest demonstration took place in Brazil's economic capital, Sao Paulo, a bastion of simmering dissatisfaction with Rousseff and the Workers' Party. The respected Datafolha polling agency estimated about 500,000 people took part in the demonstration, while police estimated turnout at nearly three times that number.
''There is a situation of ungovernability,'' said Francisco Fonseca, a political science professor at Pontifical Catholic University in Sao Paulo. ''The president has few cards.''
Fonseca added, though, that the protests showed a ''generalized discontent with the political system'' without necessarily shoring up any particular opposition party or politician.
Crowds in the yellow and green hues of the Brazilian flag brandished signs reading ''Workers' Party out.'' But demonstrators across Brazil stressed that their anger extended well beyond Rousseff and her party, saying the ''Car Wash'' investigation into corruption at Petrobras has compromised the entire political class.
''Of course I want to see Rousseff booted out,'' said Maria de Lima Pimenta, a retired schoolteacher who was at the anti-Rousseff march along Rio's Copacabana Beach. ''But then the problem becomes, who will replace her? They're all crooks.''
Protest organizers also stressed that the movement isn't linked to any opposition political party, and signs endorsing parties were largely absent from the demonstrations.
Several top politicians did turn out, including Aecio Neves, the opposition politician who narrowly lost to Rousseff in the 2013 presidential run-off election, and Sao Paulo state Gov. Geraldo Alckmin. But both were booed, and like other politicians who ventured out to the demonstrations, they beat a rapid retreat.
The uncontested star of the protests was Sergio Moro, the federal judge in charge of the Petrobras case. While demonstrators denounced politicians of all stripes who have been implicated in the scandal, many brandished signs thanking Moro.
The Petrobras scandal has ensnarled key figures from Rousseff's party, including Silva, as well as members of opposition parties.
Political tensions in Brazil have spiked since earlier this month when Silva was briefly detained by police for questioning as part of the Petrobras probe. Silva's supporters and detractors scuffled in front of his apartment in the Sao Paulo area. On Wednesday, the tension rose again when Silva was hit with money-laundering charges in a separate case.
Rousseff said at a Friday news conference that she would not quit, saying it was objectionable to demand the resignation of an elected president without concrete evidence the leader had violated the constitution.
''If there is no reason to do so, I will not step down,'' she said, calling on journalists at the event in Brasilia to ''at least attest that I don't look like someone who is going to step down.''