The companies are accused of corruption in the 2011 purchase of OPL245, an offshore oil block estimated to hold nine billion barrels of crude, for $1.3 billion.
Eni has however denied any wrongdoing in the OPL 245 transaction.
"Eni's Board of Directors has reaffirmed its confidence that the company was not involved in alleged corrupt activities in relation to the transaction," Reuters quoted Eni as saying 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," the statement added.
The Italian giant insisted in particular that "chief executive, Claudio Descalzi was not involved in the alleged illegal conduct".
