Correction: This story was changed from an earlier version to indicate Gazprom owns 56% of energy company NIS in Serbia.

KIEV, Ukraine (TheStreet) — Over the past two decades, as Russia grew to provide more than one-third of the European Union’s natural gas, state-controlled OAO Gazprom has assembled a network of holding companies, ownership stakes in energy and finance firms, and the support of friendly politicians across both continents that has allowed President Vladimir Putin to use the mammoth energy company’s web of influence as a tool of Russian statecraft.

With tentacles in 20 European states, Gazprom’s hold over the economies of several European countries has helped Putin bolster a buffer zone of Russian-leaning, former communist states on the eastern edge of the EU that have outsized influence over policies affecting his homeland.

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“Energy exports and energy policy have been a key tool of Russian geopolitical strategy for a very long time,” says Charles Hecker, global research director at Control Risks, a consulting firm in London. “It’s enshrined in the country’s national security approach.”

Russia and Ukraine gas talks deadlocked; watch the video below for details:

This long-standing strategy has become more evident over the last six months as Russia has sought to counter tough sanctions from Europe and the U.S. over its invasion of Ukraine, punctuated by the annexation of Crimea and its continuing military aid to separatist groups.

Most recently, Putin was quoted by Tass, the Russian news agency, as saying he expects talks with the Ukraine this week to resolve an ongoing dispute over its debt to Gazprom, restarting the much-needed flow of Russian gas to the country in time for the winter months. However, he added that should an agreement not be reached, “a crisis is possible.”

Gazprom not only supplies gas to Eastern Europe and 18 European Union countries including Germany, France and the U.K., it also owns a significant part of the hundreds of miles of pipelines as well as exploration and trading infrastructure in nearly every European country that uses natural gas.

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