Fatih Birol, the executive director of the Paris-based International Energy Agency, said the cutoff was a “weaponization of energy supplies,” while EU Commission President Ursula von der Leyen called it “yet another attempt by Russia to use gas as an instrument of blackmail.”

Bulgarian Prime Minister Kiril Petkov also called the suspension blackmail. “We will not succumb to such a racket,” he added.

Natural gas prices in Europe shot up 25% before the market opened Wednesday and then eased off but remained significantly higher.

The gas cuts do not immediately put the countries into dire trouble since they have worked on getting alternative sources for several years now and the continent is heading into summer, making gas less essential for households.

With the help of Western arms, Ukrainian forces have been unexpectedly successful at bogging Russia’s forces down, and they thwarted their attempt to take Kyiv. Moscow now says its focus is the capture of the Donbas, the mostly Russian-speaking industrial region in eastern Ukraine. The U.S. pressed its allies Tuesday to move “heaven and earth” to ensure Kyiv remains well-supplied with the weapons necessary for that battle.

The West has also sought to isolate Russia economically, by imposing punishing sanctions — but European countries have struggled to reduce their dependence on Russian energy. Wednesday’s cuts and threats marked a major economic counteroffensive by Moscow.

Europe is not without its own leverage since, at current prices, it is paying some $400 million a day to Russia for gas — money Putin would lose in case of a complete cutoff. Russia can, in theory, sell oil elsewhere — to India and China for instance — because oil primarily moves by ship. But the gas pipeline network from the huge deposits in the Yamal Peninsula in northwestern Siberia to Europe does not connect with the pipelines running to China. And Russia has only limited facilities to export super chilled liquefied gas by ship.

Hence, even a partial stoppage marked a “historical turning point in the bilateral energy relationship” between Russia and Europe, said Simone Tagliapietra, senior fellow at the Bruegel think tank in Brussels.