The trial of top executives from oil majors, Eni and Shell, over alleged corruption in the controversial Malabu scandal has been adjourned.
The trial kicked off on Monday with a brief procedural hearing and a decision to re-adjourn to June 20. The Milan court said it would assess requests from third parties, including a series of international non-profit organisations, to join the case at the next hearing.
The Malabu case involves the 2011 purchase by Eni and Shell of Nigeria's OPL-245 offshore oilfield, reputed as one of Africa's most valuable oil blocks, for about $1.3 billion.
Italian prosecutors had earlier indicted Shell and Agip for their role in the 2011 deal in which the Nigerian government acted as mediator between a shady company, Malabu, and the two oil majors.
A former petroleum minister, Dan Etete, and a former Attorney-General, Bello Adoke, are amongst several Nigerians indicted in the deal, which was approved by former President Goodluck Jonathan.
Shell and Eni's Nigerian subsidiary, Agip, are among those already being prosecuted in Nigeria, although they have denied wrongdoing.
Milan prosecutors allege bribes were paid to win the license to explore an oil block that holds an estimated 9 billion barrels of oil but which has never entered into production.
Part of the block is now being processed by the oil firms in deals supported by the Nigerian government despite the prosecution of the firms and indicted officials.
Global Witness, a campaign group that has conducted its own investigations, has described the case as one of the biggest corruption scandals in the history of the oil industry.
Reuters reports that at Monday's hearing Domenico Schittar, a lawyer representing the Nigerian government, said he was stepping down from his role. According to his comments in a signed document seen by Reuters, Mr Schittar said he had given up on a mandate which he said had become "awkward".
Eni CEO, Claudio Descalzi, and former Shell Foundation Chairman, Malcolm Brinded, who are standing trial along with 11 other defendants and the two companies have denied any wrongdoing.
The case suffered delay earlier in March when the court which had been due to hear the trial announced it had too many cases and could not guarantee that it would do so in a reasonable period of time.