Russia's natural gas monopoly Gazprom and companies from four European nations signed agreements Friday advancing the South Stream pipeline, pushing forward with a project that has stirred concerns about increasing European dependence on Russian supplies. The Russian-lobbied project could hamper European Union plans for a separate pipeline that would carry gas from the Caspian Sea westward and reduce EU energy dependence on Moscow. South Stream is to pipe gas westward from Russia across the Black Sea on a route that bypasses Ukraine, whose bitter price battles with Moscow have prompted Russian cutoffs that have decreased supplies to European nations. Those problems have led the EU to seek to diversify its import routes and Russia to seek to diversify its export routes. With Russian Prime Minister Vladimir Putin and Italian Premier Silvio Berlusconi looking on, Gazprom CEO Alexei Miller and the CEO of Italy's Eni, Paolo Scaroni, signed a deal Putin said would enable organizers to double the planned capacity in the offshore section from 31 billion cubic meters to 63 billion cubic meters a year. Miller also signed separate agreements with energy companies from Greece, Serbia and Bulgaria that foresee cooperation on feasibility studies, design, construction and operation of South Stream sections in those countries, Gazprom said. Russia also expects to sell gas from the pipeline to Hungary and Austria.