Sao Paulo: "I am for Dilma, in defense of democracy, but I am also against corruption," Gerson Tadeu Conti, a doctor, 67, told AFP outside the headquarters of Petrobras, in Sao Paulo.
Nearly 150,000 people rallied around Brazil, said the Single Confederation of Workers (CUT). Police put the number at 32,000.
They were also demanding political and agrarian reform, and an end to corruption.
In Rio de Janeiro, a range of speakers - student representatives, trade unionists, petroleum workers, bank employees - all took turns to speak to the crowd from the top of a truck in the city center, before marching to a Petrobras office.
"I defend Petrobras because it's our heritage. But I also want politicians to be able to manage without corruption because it affects the image of our country," Rubens Pessanha, 50, an oil sector worker, told AFP.
Friday's protests mark the beginning of what promises to be a turbulent few days for the under pressure Rousseff, with growing calls for a major turn-out against her on Sunday.
Just months into a new term, her ruling coalition has been badly tainted by the graft scandal that has enveloped Petrobras, Brazil's biggest company and once a source of pride for many in the country.
Dozens of political figures - some close allies of Rousseff - and former Petrobras executives are under suspicion over a scheme facilitating corruption and money laundering that saw an estimated $3.8 billion creamed off inflated contracts over a decade.
Nobody has yet been convicted, but some of the alleged wrongdoing took place while Rousseff was chairwoman of the Petrobras board. She is not being investigated.
Tens of thousands of people demonstrated across Brazil on Friday in support of scandal-plagued state oil giant Petrobras and in defense of democracy, ahead of a weekend protest against President Dilma Rousseff.
Protesters hit the streets in 24 state capitals around the country, including a wet Sao Paulo, where organizers estimated 100,000 people marched in a defiant and colorful rally, as police kept a close watch.
Many wore the red of Rousseff's ruling Workers' Party.
Nearly 150,000 people rallied around Brazil, said the Single Confederation of Workers (CUT). Police put the number at 32,000.
Advertisement
In Rio de Janeiro, a range of speakers - student representatives, trade unionists, petroleum workers, bank employees - all took turns to speak to the crowd from the top of a truck in the city center, before marching to a Petrobras office.
Advertisement
Friday's protests mark the beginning of what promises to be a turbulent few days for the under pressure Rousseff, with growing calls for a major turn-out against her on Sunday.
Advertisement
Dozens of political figures - some close allies of Rousseff - and former Petrobras executives are under suspicion over a scheme facilitating corruption and money laundering that saw an estimated $3.8 billion creamed off inflated contracts over a decade.
Advertisement
COMMENTS
Advertisement
Elon Musk's X To Close Brazil Operations Over "Censorship Orders" Probe Reveals Brazil Plane Crashed One Minute After Pilots Sensed Trouble Explained: What Caused Brazil Plane Crash That Killed 62 Passengers? Should Kolkata Top Cop Be Interrogated? Trinamool Leaders Differ Indian-Origin Family, On Way To Daughter's College, Killed In US Car Crash BJP Leader, 2 Doctors Summoned Over 'Fake News' On Kolkata Rape-Murder Should Kolkata Top Cop Be Interrogated? Trinamool Leaders Differ "They Were Men": Trump Again Slams Olympic Gold Medalists Amid Gender Row Questions That CBI Asked RG Kar Hospital Ex-Principal Over Kolkata Horror Track Latest News Live on NDTV.com and get news updates from India and around the world.