According to one of the sources, who asked not to be named due to the sensitivity of the matter, the executive Mariano Marcondes Ferraz was cited in a 2014 plea deal by Petrobras director Paulo Roberto Costa in connection with a bribery allegation.

Representatives for Trafigura and the federal judge overseeing the long-running Petrobras probe did not immediately respond to requests for comment.

In 2013, Trafigura and an Abu Dhabi sovereign wealth fund won control of a Brazilian iron ore port, formerly controlled by fallen tycoon Eike Batista, in a $996 million deal.

(Reporting by Guillermo Parra-Bernal; Editing by Ana Mano)