Russian energy giant Gazprom says it has halted gas exports to Poland and Bulgaria over the countries’ refusal to pay for supplies in roubles.
The firm said services will not be restored until payments are made in the Russian currency.
It comes after Russian President Vladimir Putin ordered “unfriendly” countries to pay for gas in roubles.
Poland confirmed supplies had stopped, but Bulgaria said it was still unclear whether supplies had been halted.
Countries pay in advance for their gas, but as they have gone to pay for future supplies, Russia has stood firm on its demand made last month that new purchases need to be paid in roubles.
The threat, in which Mr Putin said “existing contracts will be stopped”, has been seen as an attempt boost the rouble, which has been hit by Western sanctions.
Any country refusing to bow to the Kremlin’s demands to pay for natural gas in rubles will face the same fate as Poland and Bulgaria, Moscow warned after those two countries saw their deliveries drop to zero on Wednesday.
“Payment in proper form will be the basis for the continuation of supply,” said Kremlin spokesperson Dmitry Peskov, referring to a March 31 decree signed by Russian President Vladimir Putin demanding that all gas payments be made in rubles.
The European Commission insisted on Wednesday that payment to Russia in rubles is forbidden as it undermines sanctions imposed after it invaded Ukraine.
“Our guidance here is very clear,” said Commission President Ursula von der Leyen. “If this is not foreseen in the contract, to pay in rubles is a breach of our sanctions.”