Russia has responded to the West’s escalating arms shipments and economic penalties by halting national gas supplies to Poland and Bulgaria as well as threatening further unspecified retaliation. It was the toughest response yet against the USA-led alliance that Vladimir Putin, Russia’s president, has accused of waging a proxy war following the invasion of Ukraine.

The cut off was clearly a warning sign that Germany – hugely dependent on Russian gas – could be next. Russia is sending a message that it believes it could bring considerable pain to Europe without firing a shot. European natural gas prices surged as much as 28 % on 26 April, and the euro’s value fell to its lowest point against the dollar in five years.

Ursula von der Leyen, president of the European Commission, commented that the EU had been preparing for the possibility that Russia might halt natural gas deliveries. Nonetheless, she said, the Russian move was an attempt “to use gas as an instrument of blackmail.” Poland and Bulgaria will receive gas from EU countries but have ample stocks for the immediate future.

The stated reason for halting gas deliveries was the refusal by Poland and Bulgaria to pay in rubles, a new requirement Russia announced in March, despite the fact that its foreign contracts generally call for payment in dollars or euros. Compliance would subvert the EU’s financial sanctions on Russia and help prop up the battered ruble.