The phone discussion among the leaders came at the end of a week in which executives of the giant Russian gas company, Gazprom, stumped across the European capitals, rallying support from customers and suppliers against increased tensions and making the case that Russia and Europe were long-term economic partners who should not let temporary crises cut their ties. Gazprom is 50 percent owned by the Russian government.

“Sanctions will not help anybody, they would not just hurt Russia, but also Germany and Europe as a whole,” Mr. Seele of Wintershall has said.

Alexander Medvedev, the No. 2 at Gazprom, said that his company had done everything possible to keep gas flowing to both Ukraine and Europe, but that the time of a financial reckoning was near, alluding to the $18.5 billion that he said Ukraine owed. How, he asked, can a publicly traded company like Gazprom keep contractual promises and make needed investments with such a cash shortfall from a slippery customer? Perhaps, he suggested, Ukraine’s Western friends would like to help meet these bills.

About a quarter of the European Union’s gas supplies originate in Russia. More than half of Russia’s exports go to the European Union, and 45 percent of its imports come from the European Union, according to European statistics.

The pace at which the Ukraine crisis is changing the economics and geopolitics of Europe became clear again on Friday when Ms. Merkel endorsed a suggestion from Prime Minister Donald Tusk of Poland for a common energy policy for the 28-nation European Union. But even the general embrace of the idea by Germany suggests that European Union countries might be prepared to pull together with the kind of unified response that Russia and Russian businesses fear could lead to Moscow’s isolation.

No European industry has been as open in its support of Russia as the energy industry. Executives have publicly voiced skepticism about the effectiveness of sanctions, lobbied behind the scenes to head them off and traveled to Russia, on at least one occasion to pose with Russia’s president, Vladimir V. Putin. And the Russians, while publicly playing down the effects of sanctions, have been trying to exert influence in Brussels and elsewhere, lobbyists said.

In an interview on Friday, Gerhard Roiss, the chief executive of the Austrian oil and gas supplier OMV, which has been working with Gazprom for five decades, said, “You cannot talk about sanctions if you don’t know the outcome of sanctions.”