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Mr. Roiss met with Gazprom's chief executive this week and reaffirmed their business ties. He pointed out that this was hardly the first political crisis the sides had faced. The year Russian gas first started flowing into Austria, 1968, was the same year the Soviets invaded the former Czechoslovakia. "We've had a crisis situation several times, but if you see it over the 50 years, natural gas was not used as a weapon, and we should not use gas as a weapon," he said.
Before the call between the European leaders and Mr. Obama, Ms. Merkel called Mr. Putin in what appeared to be a last warning to fulfill the accord reached in Geneva last week to reduce tensions in Ukraine. Minutes later, a Kremlin statement put a different spin on the call, saying that both Mr. Putin and Ms. Merkel had called for three-party talks on Russian gas supplies to Europe through Ukraine.
Whether that was an indication that Mr. Putin now feared that tough sanctions loom — sanctions that Western leaders argue would inflict more harm on Russia's heavily oil- and gas-dependent economy than on Europe — was not clear.
Mr. Medvedev's tour of Europe, and what he said was constant contact with the European Union's energy commissioner, Guenter Oettinger, suggested that Russian business was very worried about losing what it has carefully built.
Do not forget, Mr. Medvedev urged Europe, that Gazprom has for decades — right through the Cold War and multiple East-West crises — been a reliable supplier. It has no intention of leaving customers in the lurch now.
"We are not planning to cut gas to Ukraine," Mr. Medvedev said. "We just would like to receive payment for the gas that we are going to deliver."
In 2006 and especially 2009, when Ukraine and Russia were locked in disputes over natural gas prices, European customers experienced delivery shortfalls for which Gazprom blamed Ukraine's siphoning of supplies intended for Europe to meet its own domestic needs.
"There never were, are not and won't be plans to cut" delivery, Mr. Medvedev said of the current situation. For one thing, he added, "we are too much dependent on the cash flow from Europe."
Russian business — not to mention rich Russians who have eagerly bought property everywhere from London to France, Berlin and the Czech spa city of Karlovy Vary — is now not just embedded in the energy supply and financial markets of Europe. As any soccer fan could see in the Champions League matches this week, Gazprom is a main sponsor of the sport in Europe.
Whether that has bought much independence from the image of the Russian government is questionable. Pressure has risen markedly on German business since Joe Kaeser, the chief executive of Siemens, met Mr. Putin in late March. Mr. Kaeser was not admonished outright, but Ms. Merkel had a distinctly frosty face for him two days later when both attended a signing of new contracts with China.
BP has a 19.75 percent stake in Rosneft, the Russian oil giant. "We're monitoring the situation, and clearly we're committed to our investment in Russia," said Toby Odone, a BP spokesman. "People keep asking us to speculate what would happen if such and such a sanction were imposed, and we're not going to do that. As things stand, our interests in Russia have not been affected by the measures that have so far been imposed."
Mr. Roiss said he had spoken to officials "on the European level and on the national level."
"This is not an issue of lobbying, it's an issue of saying what you think," he said. "My feedback from talking to politicians, wherever they are, is that people see that this is quite a broad issue, that one should not really mix too much into politics."