The Russian gas giant Gazprom and the Italian Eni group agreed Friday to a major increase in the capacity of the planned South Stream gas pipeline.

In a deal agreed at the Russian Black Sea resort of Sochi, the two firms said they would up planned production from 31 billion cubic meters per year to 63 billion cubic meters for the pipeline to be built under the Black Sea.

The agreement was signed in the presence of Russian Prime Minister Vladimir Putin and Italian PM Silvio Berlusconi.

Gazprom on Friday also reached agreement with EU members Bulgaria and Greece, and with Serbia on details of the construction of the South Stream pipeline in the countries.

The South Sea pipeline is in direct competition with the EU-backed Nabucco pipeline project, which will pump gas from the Caspian Sea to Europe, bypassing Russia.

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