The agreement, signed in the presence of Russian Prime Minister Vladimir Putin and his Italian counterpart Silvio Berlusconi, is seen as emphasizing Russia's determination to create new export routes for its gas that will avoid Ukraine.

At the meeting, held in the Black Sea port of Sochi, Gazprom also signed deals with the main energy companies of Serbia, Bulgaria, and Greece, three of the key transit countries for the pipeline, which will run from Russia under the Black Sea to Bulgaria.

About 80 per cent of the gas Russia currently exports to Europe transits Ukraine, and this has given rise to some serious recent problems. In an effort to avoid further disputes, Russia is trying to gain control of Ukraine's natural gas network, so far without success.

ENI and Enel, another Italian energy company, also agreed to sell half of their jointly-owned natural gas company, SeverEnergia, to Gazprom. ENI and Enel acquired SeverEnergia in April 2007, at the bankruptcy auction for Yukos, the private oil company effectively nationalised by the Kremlin. Gazprom will buy 51 per cent of SeverEnergia, which owns gas fields in Siberia, for $US1.5 billion.