Russia's gas giant Gazprom has warned Europe that any disputes with Ukraine could potentially lead to a disruption of gas exports to Europe.
Europe is dependent on Russian energy supplies. Around 30 percent of EU's gas comes from the country.
A payment row between Gazprom and Ukraine in 2009 resulted in gas shortages in several European countries.
European Union foreign ministers added 13 people to their visa ban and asset freeze list over Ukraine's crisis.
Well that’s the voting over, and no surprises so far. A ‘Yes’ vote claimed to be 89% in Donetsk, and suddenly Ukraine is no more.
Nearly 90 percent of voters in eastern Ukrainian region voted for self-rule, the head of the separatist election commission said.