Commerce Secretary Wilbur Ross gestures as he leaves after addressing delegates at the annual Confederation of British Industry (CBI) conference in east London on Nov. 6. (Daniel Leal-Olivas/AFP/Getty Images)

Several Senate Democrats are calling for new hearings and an inspector general's investigation into Commerce Secretary Wilbur Ross after a trove of leaked documents showed he has interests in a company with ties to Russian President Vladi­mir Putin's son-in-law.

The calls from Democratic members of the Senate Commerce Committee were prompted by reports detailing how shipping company Navigator Holdings, in which Ross holds a stake, did business with Russian energy company Sibur, which is partially owned by Putin's son-in-law Kiril Shamalov and Russian oligarch Gennady Timchenko, Putin's close friend.

"Sec. Ross's stake in company so closely tied to Putin inner circle raises profound question: Can he put America's interests before his own?" Sen. Richard Blumenthal (D-Conn.), who is among the senators calling for hearings and an IG investigation, tweeted Monday.

Ross is the second Cabinet secretary in a week to come under fire over revelations they either had or were aware of members of Trump's campaign who had closer ties to Russia than were disclosed to lawmakers during official testimony. Last week, Senate Democrats pounced on Attorney General Jeff Sessions after court papers revealed he had attended a meeting where Trump campaign adviser George Papadopoulos offered to broker a meeting between Trump and Putin through contacts. Sessions had told senators under oath that he was not aware of anyone in the campaign who had discussed meeting with the Russians.

[Democrats demand that Sessions explain his meeting with Papadopoulos]

Notably, Republicans did not rush to Sessions's defense. In comments to CNN, Sen. John Cornyn (R-Tex.), the Senate's second-highest-ranking Republican, said Democrats' questions about the meeting Sessions attended with Papadopoulos were "a legitimate area of inquiry."

But Democrats are getting no similar support from Republicans in their effort to compel a reckoning from Ross over his newly alleged Russia ties.

Ross listed Navigator Holdings among the assets and income he disclosed during his confirmation process, but provided no details about the company's connection to businesses owned by members of Putin's inner circle. During his fairly uncontentious confirmation hearing in January, Democrats focused on trade, not scrutinizing the Navigator Holdings interests or Ross's potential business connections to Russia.

"The Navigator Holdings disclosure was not a subject of questions during his confirmation hearing," Frederick Hill, a spokesman for Senate Commerce Committee chairman John Thune (R-S.D.) said Monday. "The committee expects Secretary Ross will follow the advice of his department's ethics officials should there be a determination that any holding creates a conflict of interest."

For many Senate Commerce Committee Democrats, the information in the newly leaked documents, known as the Paradise Papers, are only the latest ethical complaint against Ross. Last month, six committee Democrats wrote to the U.S. Office of Government Ethics (OGE) to complain that Ross had failed to disclose the source of almost $2 billion in assets, following a report in Forbes suggesting he had undervalued his net worth in his financial disclosure statements.

The OGE informed these senators last week that it has asked the Commerce Department for information relating to the matter.

Sen. Tammy Baldwin (D-Wis.), who co-signed the OGE letter, added on Monday that she has been waiting for the Commerce Department to answer questions about Ross's potential ties to rival foreign governments — including Putin, the state-owned Chinese Investment Corporation, and his stake in the Bank of Cyprus — for more than eight months.

"We should get to the bottom of this," said Baldwin, who opposed Ross' nomination over such concerns. She added that in light of "recent revelations," a Commerce Committee hearing and an inspector general investigation were also needed.

Sen. Maggie Hassan (D-N.H.), who was also part of the committee Democrats' letter to the OGE, said through spokeswoman Ricki Eshman on Monday that she is "deeply concerned" about Ross's business interests, "which could pose any number of troubling conflicts of interests with Russia," and called for "transparency, accountability and disclosure to look into all of Secretary Ross's potential conflicts of interests."

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