Ferreira had been on a leave of absence since Sept. 14, and Nelson Carvalho replaced him on an interim basis. In a securities filing, the company known as Petrobras (>> Petroleo Brasileiro SA Petrobras) said Carvalho would stay in that position until the board convened to elect a new chairman.

Ferreira, who has been chief executive officer of Brazilian iron ore miner Vale SA (>> Vale SA) since 2011, became Petrobras chairman of Petrobras in April, as the company was sinking deeper into its the worst crisis in history.

Prosecutors have accused Brazil's leading engineering firms of colluding to fix prices on contracts with Petrobras and other state companies and kicking back bribes to members of the ruling coalition, in what is considered as the country's worst corruption scandal ever.

(Reporting by Guillermo Parra-Bernal and Reese Ewing; Editing by Jason Neely and Lisa Von Ahn)

Stocks treated in this article : Vale SA, Petroleo Brasileiro SA Petrobras