The U.S. treasury secretary said he told U.S. lawmakers that President Donald Trump will keep strict sanctions on Oleg Deripaska, as congressional Democrats turned up pressure on the administration's policy toward the Kremlin-connected oligarch.

Steven Mnuchin released a statement on January 10, ahead of a classified briefing he was requested to give a key House of Representatives committee.

Congress has been reviewing an administration’s decision announced in December to lift sanctions against three companies that Deripaska controls: Rusal, EN+, and JSC EuroSibEnergo.

Early last year, the Trump administration indicated it was planning to sanction Rusal-- one of the world’s largest aluminum companies-- but that announcement roiled global markets, sending metal prices soaring.

The Treasury Department delayed imposing the sanctions several times, amid a reported lobbying campaign by Deripaska’s companies.

In December, the administration notified Congress it would lift the sanctions. That triggered a clause in Congress that gives lawmakers 30 days to try to reverse the decision by passing a joint resolution of disapproval.

In his statement, Mnuchin said Deripaska remained under sanctions and "his property and interests remain blocked, and any companies he controls are also sanctioned."

House Democrats, however, were publicly angry, with the leader of the chamber, Nancy Pelosi, calling it "one of the worst classified briefings we've received from the Trump administration."

"He answered some questions, but he didn’t give testimony. They had an intelligence briefing, which I won’t go into, and then they read a document that was unclassified, wasting the time of members of Congress,” she told reporters after the briefing.

Deripaska is a billionaire tycoon who made his fortune in aluminum and metals trading. He was barred from entering the United States in the 2000s, on allegations of ties to organized crime.

He was also a business partner of Paul Manafort, Trump's campaign chairman during part of the 2016 presidential election.

With reporting by NBC