BRUSSELS — Prices for natural gas futures in Europe jumped by more than 23 percent as trading began Wednesday morning, hours after Russia’s state-run Gazprom told Poland and Bulgaria it had cut supplies of the fuel.
Gazprom’s move came just as the United States and its allies agreed to send more arms into Ukraine to help the country defend its territory against the Russian invasion.
The market reaction underscored that a crucial, dreaded moment in the war was here: severe disruption to Russian natural gas exports to the European Union.
Poland and Bulgaria rely heavily on Russian gas exports, as does Germany, the bloc’s de facto economic and political leader and a holdout in efforts to swiftly impose more sanctions against Russia’s energy sector.
Fair spring weather in Europe at the moment may soften the immediate blow of the gas cutoff, but the need to replace the Gazprom supplies with alternative sources will be urgent. There is little doubt that already high gas prices will rise further, ultimately pushing up already high inflation rates and hurting consumers across the European Union.
In response to the news, Ursula von der Leyen, the president of the European Commission, said in a statement on Wednesday morning that the bloc had been preparing for Russia’s gas supply cutoff.
“The announcement by Gazprom that it is unilaterally stopping delivery of gas to customers in Europe is yet another attempt by Russia to use gas as an instrument of blackmail,” she said, adding that she was working with allies to secure gas supply for affected member states and that the institution’s gas coordination group was meeting on Wednesday morning to craft a response.
The European Union has so far imposed sanctions on Russian coal, which both Poland and Germany use heavily, and has been preparing the details of an oil embargo. But an embargo on Russian gas has long been viewed as a Rubicon not to be crossed by the European Union because of how heavily reliant Germany and other countries are on it for heating and energy production.
Now it seems that Russia has decided to move first and block the gas exports itself, after E.U. countries refused to pay for gas imports in rubles, as President Vladimir V. Putin had demanded.
Mr. Putin is desperate to get paid in the Russian currency because his ability to convert dollars and euros to rubles, which he can then use for his war effort in Ukraine, has been diminished by steps that forbid financial institutions in Europe and the United States from dealing with the Russian central bank.
On Wednesday morning, Bulgaria’s energy minister, Alexander Nikolov, said his country had sufficient gas supplies for one month and was seeking alternatives.
“Bulgaria will not negotiate under pressure and with its head bowed. Bulgaria does not give in and is not sold at any price at any trade counterparty,” Mr. Nikolov said. “Obviously, natural gas is used as a political and economic weapon,” he added.
Polish officials struck a similarly confident tone on Tuesday evening. Poland’s climate minister, Anna Moskwa, played down the effect of Russia’s decision, insisting at a news conference in Warsaw that “we are ready to be fully cut off” from Russian gas.