Picture released by Brazilian agency Fotos Publicas showing Brazil's President Dilma Rousseff (L), candidate of the Workers' Party (PT) for October's presidential election, and the candidate for governor of Rio, Lindberg Farias (C), greeting supporters during a campaign rally, in Alcantara, Rio de Janeiro, on September 12, 2014. Rousseff will face environmentalist Marina Silva, candidate for the Brazilian Socialist Party (PSB), and Senator Aecio Neves, candidate for the Brazilian Social Democratic Party (PSDB). AFP PHOTO/Fotos Publicas/Tasso MARCELO
Brazil's President and presidential candidate of the Workers' Party (PT) for re-election Dilma Rousseff (L), an Brazilian former president Luiz Inacio Lula da Silva (R) acknowledge the audience during a meeting in Rio de Janeiro, Brazil, on September 15, 2014. Brazil will hold general election next October 5. AFP PHOTO / YASUYOSHI CHIBA
Brazil's presidential candidate for the Brazilian Socialist Party, Marina Silva speaks during a campaign meeting with artists in Sao Paulo, Brazil, on September 15, 2014. The Brazilian general elections will take place next October 5. AFP PHOTO / NELSON ALMEIDA
A bus set ablaze during clashes between the Riot Police and members of the Homeless Workers' Movement (MTST) during the eviction of an abandoned hotel, burns in downtown Sao Paulo, Brazil, on September 15, 2014. Some 200 families were living in the building. AFP PHOTO / NELSON ALMEIDA
Supporters of Brazil's President Dilma Rousseff, candidate of the Workers' Party (PT) for October's presidential election, demonstrate against corruption in the state oil company Petrobras, in Rio de Janeiro on September 15, 2014. Petrobras is facing a growing scandal over kickbacks from contracts, after a former director of the company, now in custody, named dozens of politicians -- most from Rousseff's party -- as involved. Rousseff will face environmentalist Marina Silva, candidate for the Brazilian Socialist Party (PSB), and Senator Aecio Neves, candidate for the Brazilian Social Democratic Party (PSDB). AFP PHOTO/VANDERLEI ALMEIDA
A supporter of Marina Silva, presidential candidate of the Brazilian Socialist Party (PSB) holds a Brazilian flag with a Marina sticker during a campaign rally in Ceilandia, Brasilia, Brazil on September 14, 2014. The Brazilian general elections will take place next October 5. AFP PHOTO/EVARISTO SA
Brazil's presidential candidate for the Brazilian Social Democratic Party (PSDB), Aecio Neves, attends a campaign meeting with female supporters in Sao Paulo, Brazil, on September 17, 2014. Brazil will hold general elections on October 5. AFP PHOTO / NELSON ALMEIDA