Moscow appears to be making good on a threat to halt gas supplies to countries that refuse President Vladimir Putin’s new demand to pay for the crucial fuel in rubles. Europe has said that doing so would breach sanctions and strengthen Russia’s hand. Poland has been particularly vociferous in its criticism of Russia and has refused to comply with the new terms.

Poland’s main gas supplier PGNiG said it’s been told that all flows will stop from Wednesday. Minutes earlier, Russian gas giant Gazprom PJSC issued a warning that Poland must pay up for its gas supplies — on Tuesday and in the Russian currency.

“I can confirm we’ve received such threats from Gazprom which are linked among other things to the means of payment,” Prime Minister Mateusz Morawiecki told reporters in Berlin. “Poland is sticking to the arrangements and maybe Russia will try to punish Poland” by cutting deliveries.