A firm with ties to senior members of the Hillary Clinton presidential campaign registered to lobby on behalf of a major Russian bank just weeks before a massive leak exposed the bank’s role in a web of secret financial dealings that have enriched members of Russian president Vladimir Putin’s inner circle.

The "Panama Papers" are being called "the Wikileaks of the mega-rich." Corporate documents leaked from the law firm Mossack Fonseca show how world leaders have used offshore tax havens to hide their involvement in lucrative companies and business deals around the world.

Among those companies is the Russian Sberbank, whose U.S. investment banking branch recently enlisted the services of the Podesta Group. According to its lobbying registration form, the firm will work on banking, trade, and foreign relations issues.

One of the three lobbyists working on the account is Tony Podesta, a bundler for the Clinton campaign and the brother of campaign chairman John Podesta, who co-founded the firm.

Politico reported last month that Podesta and two of the firm’s other lobbyists would be working to affect "the scope of U.S. sanctions against Russia for its role in the Ukraine conflict and whether relief is possible."

In addition to the company’s Russian parent, the lobbying registration form lists three other directly-affiliated foreign entities: Cayman Islands-based Troika Dialog Group Limited, Cyprus-based SBGB Cyprus Limited, and Luxembourg-based SB International.

According to the Organized Crime and Corruption Reporting Project, a consortium of journalists exploring the Panama Papers leak, Sberbank and Troika Dialog have ties to companies used by members of Putin’s inner circle to funnel state resources into lucrative private investments.

"Some of these companies were initially connected to the Troika Dialog investment fund, which was controlled and run by Sberbank after the bank bought the Troika Dialog investment bank. Troika and Sberbank declined to comment," the project reported on Monday.

The Mossack Fonseca documents show that Troika Dialog secretly signed away much of its interest in a Russian truck manufacturer to "an unknown offshore" called Avto Holdings. That company was partially owned by Sergei Roldugin, a close Putin friend and the godfather of the Russian president’s daughter.

The Panama Papers also reveal the existence of "similar agreements between Troika and offshore companies affiliated with Roldugin," according to the project.

"These agreements were different just in dates, names of the companies, stakes and sums of money," the project reported. "But the point remained: offshore companies affiliated with Putin’s friend had privileged rights to control large stakes in strategic Russian enterprises, to receive dividends, and to buy these stakes for laughable sums."

Despite its apparent ties to the interests of Russia’s political elite, Sberbank is officially a private company. That allows the Podesta Group to report it as a standard lobbying client, rather than a state-owned entity, which would trigger the more detailed lobbyist reporting requirements of the Foreign Agent Registration Act.

The Podesta Group did not respond to a request for comment by press time.