Italian giant Eni and fellow petroleum company Shell will stand trial in Italy over allegations of bribery and corruption in the 2011 purchase of an offshore oil block in Nigeria.

A judge in Milan ordered Eni, Shell and key figures such as Eni chief Claudio Descalzi and his predecessor Paolo Scaroni to stand trial in proceedings to begin March 5.

The companies are accused of corruption in the 2011 purchase of OPL245, an offshore oil block estimated to hold 9 billion barrels of crude, for $1.3 billion.

“Eni’s Board of Directors has reaffirmed its confidence that the company was not involved in alleged corrupt activities in relation to the transaction,” the Italian firm said in a statement Wednesday.

“Eni expresses its full confidence in the judicial process and that the trial will ascertain and confirm the correctness and integrity of its conduct,” it said.

It insisted in particular that “chief executive Claudio Descalzi was not involved in the alleged illegal conduct”.

Both companies are charged with corruption in Nigeria over the deal, which allegedly saw Nigeria’s former president Goodluck Jonathan and his oil minister pocket bribes.

Both have repeatedly maintained that they acquired the rights to the lucrative block in line with Nigerian law.