MILAN (Reuters) - Italian oil and gas group Eni ENI.MI said on Thursday its chief executive, Claudio Descalzi, was under investigation for a conflict of interest issue over dealings in the Congo.

FILE PHOTO: The logo of Italian oil and gas group Eni is seen on the facade of its headquarters in Rome, Italy, December 23, 2017. REUTERS/Alessandro Bianchi

In a statement Eni said CEO Descalzi had been served notice by prosecutors he was being probed for not disclosing certain information regarding relations between Eni’s Congo unit and a company called Petroservice. It gave no additional details.

A source close to the matter said prosecutors in the Congo probe were alleging Descalzi had not disclosed the fact that his wife, Marie Magdalena Ingoba, was behind Petroservice. Eni declined to comment.

“I firmly reject the alleged accusation. It is without any foundation,” Descalzi said in the statement.

A lawyer representing Descalzi’s wife was not immediately available for a comment.

State-controlled Eni is currently under investigation by Milan prosecutors for alleged corruption in the Congo Republic in the period between 2009 to 2015.

Descalzi, who has been at the helm of Eni since 2014, is one of the defendants in a corruption trial in Nigeria over a $1.3 billion purchase of a giant oilfield.

Eni has denied any wrongdoing in the Congo probe. The company and Descalzi have denied wrongdoing in the Nigeria case.

The source said Descalzi’s home had been searched on Thursday. This was confirmed by an Eni spokesman.

According to a search warrant seen by Reuters, prosecutors in the Congo case allege Petroservices benefited from nearly $105 million worth of contracts with Eni from 2012 to 2017. Eni acknowledged this to shareholders last year.

In Thursday’s statement Eni said it had already concluded thorough investigations - outsourced to independent, third-party consultants - which had excluded any breaches or conduct aimed at benefiting service suppliers, in particular Petroservice.

Descalzi’s second mandate as CEO at Eni expires early next year.