A federal judge in Brazil has suspended President Dilma Rousseff's appointment of former president Luiz Inacio Lula da Silva as her chief of staff as thousands protest the appointment for a second straight day.
"I hereby interrupt the nomination of Mr Luiz Inacio Lula da Silva to the position of chief of staff or any other that grants him immunity," Judge Itagiba Catta Preta said in the preliminary ruling, which must still be reviewed by a higher court and can be appealed.
Prosecutors have charged Lula with money laundering and fraud as part of its investigation into the state-owned Petrobras oil company.
As a member of Rousseff's cabinet, Lula can only be tried before the Brazilian Supreme Court.
Lula has denied involvement in the Petrobras scandal.
Some 2,000 demonstrators gathered Wednesday in the streets of Brazilia and Sao Paulo after Rousseff named Lula, who left office with very high popularity ratings, saying it would strengthen her government.
For her part, Rousseff is battling an impeachment attempt and a deep recession as well as the Petrobras scandal. Rousseff succeeded Lula in office, and some critics say they expect him to make another run for office when Rousseff's term is up.
In a twist late Wednesday, a judge investigating the Petrobras scandal released audio recordings of Lula's phone conversations indicating that he was seeking help in avoiding prosecution.
Rousseff has condemned the release as "illegal and anti-democratic."
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.
On Sunday, Brazilian police said some 3 million people across the country took to the streets to demand Rousseff's ouster.
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."
Dozens of former Petrobras executives and political figures 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.