Ukrainian oligarch Dmytro Firtash, seen here in 2011, was arrested in Vienna on Wednesday on charges of bribery and criminal conspiracy stemming from an FBI investigation. (Inna Sikolovskaya/EUROPEAN PRESSPHOTO AGENCY)

A Ukrainian oligarch with deep and lucrative ties to Russia’s state-owned energy monopoly has been arrested in Vienna at the request of the FBI, according to Austrian press accounts, in what could be the beginning of a U.S. effort to inflict financial pain on Russia over its role in the Ukrainian crisis.

Dmytro Firtash acted as Russia’s very well-paid agent, buying natural gas cheap and selling it to Ukraine’s national gas company at a steep markup. Yulia Tymoshenko, the former Ukrainian prime minister, accused him of kicking back a large portion of the proceeds, effectively creating an offshore slush fund for Gazprom — which is the primary pillar of the political-financial structure built by Russian President Vladimir

Putin.

An official statement by the Austrian police said that a “Dmytro F,” 48, was arrested Wednesday evening on charges of bribery and criminal conspiracy stemming from an FBI investigation that dates to 2006. In Kiev, the Ukrainian government confirmed that the suspect was Firtash.

The case against him stems from a deal in India, the Interfax news agency reported, citing a source in his company — but his arrest in the midst of the Ukrainian crisis will be taken as a sharp attack by the United States on Russia’s financial structure.

Gazprom is a giant source of revenue for the Kremlin, and Firtash was involved directly in one of its highest producing income streams.

1 of 62 Full Screen Autoplay Close Skip Ad × Tensions high in Ukraine as pro-Russian forces tighten grip on Crimea View Photos Russian forces tightened their grip on Crimea despite a U.S. warning to Moscow that annexing the southern Ukrainian region would close the door to diplomacy in a tense East-West standoff. Caption Crimea votes on whether the autonomous region should join Russia. March 15, 2014 Svetlana Kalisetskaya, a polling-committee chairwoman, checks a voting cabin after completing preparations for Sunday’s referendum at a polling station in Perevalne, in Ukraine‘s Crimea region. Vadim Ghirda/AP Buy Photo Wait 1 second to continue.

Tymoshenko, who made a fortune herself in the gas business in the 1990s, managed as prime minister to push Firtash and his company, RosUkrEnergo, aside in 2009. But Ukraine had to pay a steep premium to get rid of him, and went deeply into debt to the Russian energy giant.

After his election as president in 2010, Viktor Yanukovych, a rival to Tymoshenko, saw to her conviction on charges of misuse of office for arranging that deal. She was released after his ouster Feb. 22.

Last fall, after Yanukovych turned for help to Russia as protests against him started to swell, Gazprom offered Ukraine a 35 percent discount — but on the condition that Firtash return as a middleman.

Most of the natural gas that Russia sells to Europe travels across Ukraine, providing one of the largest sources of revenue for the Russian government. Firtash’s company also has a role in those sales.

In Kiev, the new government said it had not been seeking Firtash’s arrest. There was no immediate reaction here in Moscow. If Firtash is extradited to stand trial in the United States, the Kremlin will be sure to object as strenuously as it can.