UPDATE 4-Russia clinches deals to hasten Europe gas link

* Gazprom, Eni agree to boost South Stream pipeline capacity

* Gazprom pays $1.5 bln to Eni, Enel to buy-back assets

* Bulgarian, Greek, Serbian firms sign South Stream deals

* Russian, Italian PMs oversee the signing

* Gazprom: Nabucco is a political project, not economic

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By Gleb Bryanski and Stephen Jewkes

SOCHI/MILAN, May 15 (Reuters) - Russia secured more support from four European states on Friday to speed up its South Stream gas link and rebuked the United States as well as former Soviet satellite nations for backing a rival pipeline project.

The deals with Italy, Bulgaria, Greece and Serbia included a plan to double South Stream's capacity as Moscow bids to outpace the Western-backed Nabucco pipeline to bring gas from Central Asia and the Caspian to ease Europe's dependence on Russian gas.

But the deal came at a price as Russian company Gazprom (GAZP.MM) paid a premium to buy back gas assets from Italian energy firms Eni (ENI.MI) and Enel (ENEI.MI) and allowed Eni to sell Russian gas from South Stream in European transit states.

"Activities around Nabucco are being initiated by politicians, often from across the Atlantic, because it is a political not an economic project," Gazprom, Russia's gas export monopoly, said in a statement.

Italian Prime Minister Silvio Berlusconi came to Russia's Black Sea resort of Sochi to oversee the signing of deals with Prime Minister Vladimir Putin, whom he often calls his friend.

Gazprom and Eni have already set up a 50/50 venture to build South Stream, which will start near Sochi, then cross the Black Sea to reach Bulgaria, Greece, Serbia, Hungary, Italy and possibly Austria. For a FACTBOX, please see [ID:nLF362831]

Gazprom and Eni said on Friday the pipeline's capacity could ultimately be expanded to 63 billion cubic metres a year from the initially planned 31 bcm and the recently mentioned 47 bcm.

Russia supplies a quarter of Europe's gas, with exports of 150 billion cubic metres a year. Gazprom's plans, such as South Stream and Nord Stream in the Baltic region, have fed European Union fears the bloc will become yet more dependent on Russia.

"Some European politicians, mainly from new EU members, are against expansion of new offshore pipelines ... The genetic memories of their dependence on the USSR do not allow them to weigh all the pros and cons of such projects," Gazprom said.

The Kremlin is often accused of using energy as a weapon. European calls for greater diversification intensified after Russia cut gas to Ukraine twice in recent years due to pricing disputes amid icy political relations between Moscow and Kiev.

The cuts led to serious disruptions of gas supplies to Europe and Gazprom argues South Stream will ease its dependence on transit via Ukraine and boost Europe's energy security.

GAZPROM'S CONCESSIONS

On Friday, Gazprom also signed deals over South Stream with Bulgarian, Serbian and Greek energy firms, but some of the deals are not going as smoothly as planned.

Gazprom had asked Bulgaria to allow it to use the country's existing pipeline to cut on costs.

"It will be a separate pipeline," said Galina Tocheva, executive director of Bulgaria's Energy Holding. Bulgaria, the country worst affected by the latest Russia-Ukraine gas row in January, is also planning to host Nabucco. [ID:nLE210079]

With Eni, Gazprom signed only a supplement to their 2007 memorandum rather than a final agreement despite bowing to demands for joint gas marketing. Eni said it would sell 12 bcm a year from South Stream in the transit countries.

Gazprom has a long history of big deals with Eni.

In 2007, Eni and its fellow partner Enel paid $5.8 billion for Russian oil and gas assets at a state-ordered auction of assets of bankrupt oil firm YUKOS. The duo immediately agreed to resell part of the assets to Gazprom at a discount in 2009.

But the discount turned into a premium as Gazprom, Russia's most indebted company, paid $4.1 billion to buy back oil assets in April. On Friday it agreed to pay $1.5 billion for a 51 percent stake in gas assets leaving Eni and Enel with the remaining 49 percent at virtually no cost.

"The deal is of a complex nature," Gazprom Chief Executive Alexei Miller said when asked about the premium Gazprom paid.

While the fate of South Stream depends largely on financing and on its ability to reach final agreements with transit states, Nabucco needs above all to find long-term gas suppliers.

So far only global majors BP (BP.L) and Statoil (STL.OL), working in Azerbaijan, have agreed to supply gas to it, while Baku itself is considering an option to sell gas to Gazprom.

Turkmenistan, seen as the other big potential supplier to Nabucco, refused to join the project at a summit in early May in Prague, despite its uneasy relations with Moscow.[ID:nLD053519] (Writing by Dmitry Zhdannikov; Editing by Anthony Barker)