United States Secretary of Commerce Wilbur Ross shares business interests with Russian President Vladimir Putin’s family, which he failed to disclose when he was being confirmed for his cabinet position, several news outlets are reporting.

The details of Ross’s financial holdings were revealed in a stash of seven million documents, including emails, presentations and other electronic data, from Appleby, a Bermuda-based law firm, that was leaked to the German newspaper Süddeutsche Zeitung. The data was then shared with the International Consortium of Investigative Journalists and several media organizations around the world, including NBC News and The New York Times in the US.

The documents show that Ross retains an interest in a shipping company called Navigator Holdings. One of that shipping firm’s most important business relationships is with the Russian energy firm Sibur, which is controlled by Putin’s son-in-law and other members of Putin’s inner circle, including Gennady Timchenko, who is on the Treasury Department’s sanctions list and has been barred from entering the US since 2014.

The leaked documents provide a look into the world of global offshore finance. The New York Times reported that the documents contain references to offshore interests held by Gary Cohn, Trump’s chief economic adviser, and Secretary of State Rex Tillerson.

In the case of Ross, the documents provide a picture of his finances that goes beyond what he submitted to the government as part of the confirmation process. On January 15, 2017, Ross submitted a letter to the ethics official at the Commerce Department, explaining what he was doing to avoid conflicts of interest.

The billionaire Ross held financial interests in hundreds of companies in dozens of sectors, any one of which could have represented a potential conflict of interest.

A Commerce Department spokesperson said Ross recuses himself as secretary from matters regarding transoceanic shipping. The spokesperson did not address whether Ross informed Congress or the Commerce Department that he was retaining an interest in companies that have close Russian ties.

Ross’s connections to ocean shipping and to the Russian elite were already publicly known, as Ross retained an interest in Diamond S Shipping Group Inc., in which his co-investor is the Chinese government. Also known were his former holdings in the Bank of Cyprus—which has ties to a Putin confidant—although he divested that holdings as well as investments in a total of 80 entities.

According to NBC News, the leaked documents, together with an examination of SEC filings, show Ross did not reveal the full details of the holdings he kept. In a nutshell, Ross kept investments in two offshore entities with ownership interests in Navigator. These “were listed in Ross’ financial disclosure prior to confirmation,” NBC News reported, “but were not among the assets he declared he would retain. According to an SEC filing, those entities hold 17.5 million shares in Navigator, which constitutes control of nearly one-third of the shipping firm.”

Richard Painter, the chief White House ethics lawyer during the George W. Bush administration, told NBC News that Ross must recuse himself from all Russia-related matters because of his ownership interest in a company “that is doing business with Russian nationals who are either under sanctions or who could come under sanctions in any future sanctions regime.”

“That,” Painter said, “would be a criminal offense for him to participate in any such matter.”