Brazil's President Michel Temer attends the inauguration ceremony of new Ministers, at the Planalto Palace in Brasilia, Brazil, February 3, 2017. REUTERS/Adriano Machado

SAO PAULO (Reuters) - A Brazilian Supreme Court justice on Thursday authorized a probe into allies of President Michel Temer on allegations they tried to thwart an investigation into political kickbacks at state-run oil firm Petrobras, a court official said.

Prosecutor General Rodrigo Janot had earlier this week accused ex-President Jose Sarney, who now sits in the Senate, along with Senators Romero Juca and Renan Calheiros of conducting “political maneuvers” in a bid to hamper the massive investigation, known as Operation Carwash.

Sergio Machado, a former head of a unit of the state oil company, was also implicated in the scheme, the prosecutor said.

It was the first investigation authorized by Supreme Court judge Edson Fachin since he took over the Carwash probe on Feb. 2 from Justice Teori Zavascki, who died in a plane crash.

The prosecutor general produced six hours of conversations between Machado and the politicians, which Janot claims demonstrate their intent to obstruct the investigation.

Machado, who has turned state’s witness, recorded the conversations himself. In the recordings, the men discuss how they could create roadblocks to the investigation into political graft, which has cast a shadow over Temer’s center-right government.