Updated

Russian gas company Gazprom has formally started construction of a major pipeline that will deliver Russian gas to a large part of Europe.

The South Stream pipeline will connect Russia's Black Sea coast with the Balkans, Austria and Italy, carrying up to 63 billion cubic meters of gas annually. The pipeline, funded by Gazprom, Italy's Eni, France's EdF and Germany's Wintershall, is due to start operating in 2015.

Investors and industry experts have criticized the project as too costly, but Gazprom has been eager to bypass neighboring Ukraine to ensure safe shipping of its gas. Pricing and payment disputes between Russia and Ukraine have caused major disruptions in the past, cutting off gas for millions of customers in Europe.

Europe currently gets about two-fifths of its gas from Russia.