Petar Dimitrov said that the government had received a letter from the Russian Embassy in Sofia warning about the possibility of a new gas crisis if Kiev did not pay on June 7.
Bulgaria was one of the countries worst hit by the January gas dispute between Moscow and Kiev, which left thousands of people without heating and forced dozens of factories to shut down. The nation is almost fully dependent on Russian gas and has no access to alternative pipelines.
On Wednesday, Russia said it may cut gas supplies to Ukraine at the end of June or early July if Ukraine did not pay, once more threatening transit supplies to Europe.
Barely four months after that January dispute, Russia rejected a Ukrainian proposal to defer payment on up to USD 5 billion in gas storage fees. Moscow has urged the EU to help Kiev pay the bills, but the EU's response has been cool.
