Reuters - Bulgaria, heavily dependant on Russia for gas and oil, will estimate its own reserves and seek alternatives to cope with any worsening of the Ukrainian crisis, it said on Tuesday. "Several key threats can be outlined that can pose risks to Bulgarian security. They are mainly economic," Deputy Prime Minister Tsvetin Yovchev said after a meeting of the government's security council over Ukraine. It meets over 85 percent of its gas needs with imports from Russia's Gazprom through only one route that passes Ukraine. Its only oil refinery, run by Russia's LUKOIL, that supplies over 60 percent of the its refined fuel in the country, gets its crude through an Ukrainian Black Sea port.