Some of Europe’s largest energy companies are preparing to use a new payment system for Russian gas demanded by the Kremlin, which critics say will undercut EU sanctions, threaten the bloc’s unity and deliver billions in cash to Russia’s economy.

Gas distributors in Germany, Austria, Hungary and Slovakia are planning to open rouble accounts at Gazprombank in Switzerland in order to satisfy a Russian requirement for payments in its own currency, according to people with knowledge of the preparations.

The groups include two of the single largest importers of Russian gas: Düsseldorf-based Uniper and Vienna-based 0MV.

Negotiations between European buyers and Gazprom, the Russian statecontrolled gas supplier, have intensified as payment deadlines approach, they said.

Italy’s Eni, another of Gazprom’s large customers, is evaluating its options, said two people familiar with the discussions. The Rome-backed company has until the end of May, when its next payment for Russian supplies is due, to make a

final call, Italian officials said.

The preparations show the impact of Russian efforts to weaponise gas supplies and challenge the EU’s ability to maintain a united front against Moscow.

Russian president Vladimir Putin issued a decree in late March that gas buyers from so-called unfriendly nations — which include all of the EU — had to set up both foreign currency and rouble bank accounts with Gazprombank, the

Switzerland-based financial trading arm of Gazprom, to pay for their supplies. The measure was seen as a way of neutralising EU sanctions against Russia’s central bank over Moscow’s invasion of Ukraine.

Gas importers in Poland and Bulgaria, which have refused to sign up to the Kremlin scheme, had gas supplies from Russia halted on Wednesday, a decision Ursula von der Leyen, European Commission president, described as being tantamount to blackmail.