Russian Prime Minister Vladimir Putin and Turkish counterpart Recep Tayyip Erdogan on Thursday signed an agreement that will allow the planned South Stream pipeline to pass through Turkey's waters, according to dpa. The pipeline is a Russian-Italian project that would bring Russian gas to Europe via the Black Sea. It is seen as a rival to the Nabucco pipeline, which some European leaders favour since that project does not rely on Russian gas. Payment disputes between Russia and Ukraine, through which much of Russian gas destined for Europe flows, have blocked gas shipments to Europe in the past, making some question Russian reliability. Bypassing Ukraine with the South Stream pipeline should resolve that problem, argue Russian officials. Nonetheless, some European leaders would like an alternate, worrying that they are too dependent on Russia, which provides the bulk of gas for European consumption.