The former leader and mentor to current suspended President Dilma Rousseff, known as Lula during his 2003-2010 presidency, is accused of hampering Operation Car Wash, the investigation into alleged corruption at the state oil firm Petrobras.

"The charge is obstruction of justice" linked to the Petrobras embezzlement probe, a spokesman for the Justice Ministry said Friday. Silva had been under investigation in various jurisdictions but has now officially become a defendant.

Dozens of politicians and executives have been accused of embezzlement from the state oil company Petrobras in a bribes-for-contracts network which lasted for most of Silva's presidency.

The 70-year-old founder of the leftist Workers' Party has denied any wrongdoing. "The defense argues that the charges are based uniquely on [evidence from] a plea bargain," a statement from his spokesman said Friday.

UN petition

Silva's lawyers have petitioned the United Nations, alleging his human rights were violated in the investigation. They have criticized federal Judge Sergio Moro, who presides over most of the cases in the Petrobras investigation and has ordered the arrest of dozens of executives over the past few years.

"Lula is a victim of abuse of power by a judge, with the complicity of prosecutors and the media," the petition said. Silva hopes the UN "will not only provide some compensation for the violation of his rights, but also help future governments draft laws and procedures that can improve the fight against corruption while protecting the basic rights of suspects."

Representing Silva at the UN, British human rights lawyer Geoffrey Robertson said of his client on Friday: "There's no evidence that he took backhanders or kickbacks in the period when he was president."

jm/cmk (AFP, Reuters)