Bulgaria imposed a tax on Russian gas transit of BGN 20 (USD 10.80) per megawatt-hour last week, prompting reactions in Budapest and Belgrade, which receive Russian gas through Bulgaria.

Bulgarian Prime Minister Nikolay Denkov defended the move this week, saying that "there is a good chance that this [tax] would create real competition" on the gas market "from which the whole of Europe would benefit."

"We protect Bulgarian interests. These are revenues that can enter the state budget," Denkov added.