Ukraine imports 90% of its oil and most of its natural gas. Russia ranks as Ukraine's principal supplier of oil, and Russian firms own and/or operate the majority of Ukraine's refining capacity. Natural gas imports come from Russia - which delivers its own gas, as well as the gas from Turkmenistan. Ukraine transports Russian gas to the EU through its well-developed gas pipelines system, being Europe's vitally important connection. The country's dependence on Russian gas supplies dramatically affects its economics and foreign policy, especially after the 2014 Russia–Ukraine gas disputes.