SOFIA, Oct 31 (Reuters) - Russia and Bulgaria have cleared financial details on building the South Stream gas pipeline and Gazprom has started the construction of the 3.5 billion euros project in the Balkan country, Gazprom CEO Alexei Miller said on Thursday.
The project, seen as Russia's response to European Union attempts to find alternative gas suppliers, is planning to transport some 63 billion cubic metres of gas a year through the Black Sea, Bulgaria, Serbia, Hungary and Slovenia into Italy.
"The South Stream pipeline is the key element for energy security in Europe," Miller told reporters.
A first phase of the project will be ready to pump 15.75 billion cubic metres of gas to Bulgaria by the end of 2015, officials have said. (Reporting by Tsvetelia Tsolova; writing by Radu Marinas; editing by Keiron Henderson)