(Adds details about investigations and Shell comments)
MILAN, March 30 (Reuters) - Italian prosecutors areinvestigating Royal Dutch Shell as part of a probe intothe acquisition of an off-shore oil field in Nigeria, theAnglo-Dutch company said on Wednesday.
"We can confirm we have received notice of proceedings fromthe Public Prosecutor in Italy," a Shell spokesman said.
Earlier on Wednesday a judicial source told Reuters thatShell was under investigation by Milan-based judges for allegedinternational corruption.
Shell headquarters in the Hague were searched in February byDutch police and prosecutors as part of this new strand ofinvestigations, the company spokesman also said..
In 2014 a Milan court placed Eni underinvestigation over the $1.3 billion purchase in 2011 ofNigeria's OPL-245 offshore oil block by the Italian major andShell.
Prosecutors later widened their investigation to include EniChief Executive Claudio Descalzi.
Eni and Descalzi have denied any wrongdoing. Thestate-controlled oil company has always said it dealtexclusively with the government of Nigeria, paid fees into agovernment account and did not use intermediaries for thetransaction.
"Shell is cooperating with the authorities and is lookinginto the allegations, which it takes seriously," the Shellspokesman said.
"Shell attaches the greatest importance to businessintegrity, one of our core values," he added.
Italian prosecutors are working jointly with an anti-fraudteam in the Netherlands in order to determine whether the twooil companies paid bribes to obtain licences for the Nigeriansite, the judicial source said, confirming reports by Italy'sdaily Corriere della Sera.
The OPL-245 block has been at the centre of a series oflong-standing disputes.
It was initially awarded in 1998 by former Nigerian oilminister Dan Etete to Malabu Oil and Gas, a company in which hewas a shareholder.
The field was then sold in 2011 to Eni and Shell. Accordingto documents from a British court, Malabu received $1.09 billionfrom the sale, while the rest went to the Nigerian government.
The oil block is estimated to contain 9 billion barrels ofcrude oil.
Shell, which sold some Nigerian assets in 2015, has beenactive in the country since 1937.
(Reporting by Emilio Parodi, additional reporting by RonBousso, writing by Giulia Segreti, editing by Silvia Aloisi andDavid Evans)