MOSCOW, September 30 (RIA Novosti) - The CEOs of Russia's Gazprom and Italy's Eni have discussed the potential involvement of a third partner in their South Stream gas pipeline project, Gazprom said in a statement on Wednesday.

ENI is so far Gazprom's only partner in the project, designed to deliver gas to Europe via the Black Sea.

According to the Russian gas monopoly, Gazprom's Alexei Miller and Eni's Paolo Scaroni "discussed the possibility of inviting a third partner in the project to build the sea sector of the gas pipeline."

In May, the two partners signed a second addendum to a memorandum of understanding on further steps to implement the project. Gazprom also signed a package of documents on South Stream with Bulgarian, Greek and Serbian energy companies, and agreements with Austria and Slovenia were also planned.

Russian business daily Kommersant reported in mid-September that state-controlled Electricite de France planned to sign a deal with Gazprom for at least a 10% stake in South Stream.

Miller said on Monday that Turkey, Romania and a number of other countries were also seeking to participate.

A number of officials, including Russian President Dmitry Medvedev, German Chancellor Angela Merkel and her predecessor Gerhard Schroeder, who now sits on the board of another gas pipeline project, Nord Stream, recently denied that South Stream would rival to the EU-sponsored Nabucco, designed to bring gas from Central Asia and the Caspian to Europe, bypassing Russia.

The 25 billion-euro ($36.5 billion) South Stream project is designed to annually pump 31 billion cubic meters of Central Asian and Russian gas to the Balkans and on to other European countries, bypassing Ukraine, which has frequent disputes with Russia over gas supplies and transits. The pipeline's capacity is expected to be eventually increased to 63 billion cubic meters.