Glencore, Vitol and Trafigura are under investigation over alleged bribery of employees at Brazil's state-run oil company Petrobras

Brasília (AFP) - Brazil has opened an investigation into commodity trading groups Glencore, Vitol and Trafigura over alleged bribery of employees at state-run oil company Petrobras, prosecutors said Wednesday.

The probe marked a new phase in Operation Car Wash, an anti-corruption investigation opened in 2014 that has resulted in charges and convictions against many in Brazil’s corporate elite – as well as the imprisonment of former president Luiz Inacio Lula da Silva.

Prosecutors alleged the three commodity trading groups had paid $15 million in bribes to Petrobras employees between 2009 and 2014 in return for advantages such as discounted prices or extra trading deals.

Other commodity trading firms were also being investigated for alleged bribery amounting to another $16 million, they said without identifying them.

Eleven arrest warrants have been issued under the new probe, and a police source told AFP that six individuals had been arrested by late Wednesday.

Of the remaining five, four were abroad and one was in a Brazilian hospital, the source said, without giving the suspects’ nationalities.

According to the prosecutors, the alleged bribery implicated Petrobras marketing and sales employees in operations handled by its offices in the US city of Houston, as well as in its operations center in Rio de Janeiro.