Russia just escalated its war against the West, cutting off gas supplies to two European nations that refused to pay for exports in rubles. On Wednesday, Russian energy company Gazprom made good on a threat to shut off the natural gas valves to Poland and Bulgaria.

Facing crippling sanctions, Russian President Vladimir Putin recently demanded E.U. nations pay for gas exports in rubles in an apparent effort to boost the home currency. Nations typically pay for exports in euros and dollars. Poland and Bulgaria refused to make the switch, noting it could violate sanctions placed on Russia over its war in Ukraine.

European Commission President Ursula von der Leyen blasted Russia’s move to use gas as “blackmail,” and said the E.U. is working on contingency plans.

“This is unjustified and unacceptable. And it shows once again the unreliability of Russia as a gas supplier,” she said. “Our response will be immediate, united and coordinated.”

But the 27-nation bloc is shaken, and Bloomberg reported some countries have caved and made ruble payments to avoid getting cut off.

As reliant as the E.U. is on Russian energy, gas is just one more weapon in Russia’s war on Ukraine. Energy prices immediately spiked in Europe on the news as European leaders scrambled to plug the gaps.