Twin pipelines from Nord Stream, a Gazprom system, carry more than 800 billion cubic feet of Russian natural gas to European consumers each year after making landfall in Germany. Polish Prime Minister Donald Tusk said while Germany isn't the only company with ties to Gazprom, the Russian energy giant, the influence shows the strength of Russia's grip on the region's energy sector.
"In future, we will not be able to successfully resist against aggressive or expansionist steps by Russia if so many European countries will be dependent on [Russian] gas and will go even further down the road of dependence," he was quoted by the EU Observer as saying Monday.
European member states are trying to break Russia's influence on the region's energy sector by courting rival suppliers, notably in Azerbaijan.
Russian military action in Crimea, a Ukrainian peninsula, has raised concerns about the Kremlin's sway in a region that was once on the western edge of the Soviet Union.
Europe gets about a quarter of its natural gas needs met by Russia, though the majority of that runs through the Soviet-era transit network in Ukraine.