Bulgarian Prime Minister Kiril Petkov on Wednesday accused Moscow of using natural gas for "blackmail" after Russia's state-controlled energy company said it would stop supplying his country, as well as Poland. Gazprom said in a statement that it hadn't received any payments from Poland and Bulgaria since April 1 and was suspending their deliveries. This comes after Russian President Vladimir Putin said that "unfriendly" foreign customers would need to start paying for gas in rubles, Russia's currency.