Officials from Eni sought to convince a witness, a former Eni manager, to withdraw some statements he made during investigations into a Nigerian corruption case involving the Italian oil group, a court heard on Wednesday.
Prosecutor Fabio De Pasquale made the comment in a trial hearing into the case, during a legal debate over a request by Eni lawyers to adjourn proceedings to give more time to consider evidence in a related obstruction-of-justice investigation.
"We have become aware that Eni, through its managers, would have tried to influence and would have approached the defendant (Vincenzo) Armanna to convince him to withdraw some of his statements," De Pasquale told the court without elaborating.
Armanna is both a defendant and prosecution witness in the trial in which Eni is accused of acquiring a Nigerian oilfield in 2011 by corruptly paying middlemen.
Armanna declined to comment to Reuters late on Wednesday on the allegation he was approached to withdraw some of his testimony. He has always denied wrongdoing.
According to new testimony given to prosecutors by a former legal adviser to Eni, viewed by Reuters, the attempt to convince Armanna to withdraw some of his statements was directed by Eni Chief Executive Claudio Descalzi.
Lawyer Piero Amara says in the written testimony that Descalzi had authorized another Eni executive, Claudio Granata, to enlist Amara's help in persuading Armanna to withdraw some of his evidence against Eni in the corruption case.
Excerpts of that evidence, not yet revealed in court but made available to parties directly involved in the trial, were leaked in Italian newspapers on Wednesday, prompting a strong denial by Descalzi as well as a defamation suit against Amara.
Granata has also filed suit for defamation against Amara, Eni said, adding: "The claims made by Amara in his testimony filed by his defense are denied categorically."
Amara is himself under investigation for alleged obstruction of justice. His lawyer has said that Amara did nothing wrong.
Amara's lawyer, Salvino Mondello, was not immediately available for further comment on Thursday.
Eni has also denied any wrongdoing in the trial, in which it is accused of buying the oilfield in the knowledge that the vast majority of the $1.3 billion purchase price would be siphoned off to agents and middlemen in corrupt payments.
Oil major Shell, which jointly bought the field with Eni, is also on trial for corruption over the deal. It denies any wrongdoing.
While the trial against Eni and Shell enters its final stages, Milan prosecutors continue to investigate the allegations that Eni officials sought to obstruct justice in the Nigeria case. No charges have been laid.
"Eni is dealing with the (trial) proceedings with the utmost serenity and is confident that the deliberations underway will continue to confirm the company's total non-involvement with facts that never happened and have nothing to do with the group," the company said.
(Editing by Mark Bendeich, Silvia Aloisi, Edmund Blair and Nick Tattersall)