A bombshell report Wednesday that President Donald Trump's former campaign chairman Paul Manafort had been paid millions by a Russian billionaire to benefit Russian President Vladimir Putin dealt a new blow to the White House as it faces questions over possible collusion between members of Trump's presidential campaign and the Kremlin.

Manafort has confirmed his work with Russian aluminum magnate Oleg Deripaska, but denies he was acting for Putin's benefit.

"I worked with Oleg Deripaska almost a decade ago representing him on business and personal matters in countries where he had investments," Manafort said in a statement through his spokesman. "My work for Mr. Deripaska did not involve representing Russian political interests."

The White House was tight-lipped Wednesday morning, declining to comment on the report by The Associated Press that Manafort had signed a $10 million-a-year deal in 2006 with Deripaska, a Putin ally, to positively influence U.S. politics, news coverage and business dealings on Putin's behalf.

But on Wednesday afternoon, White House press secretary Sean Spicer downplayed the significance of the report, telling reporters that the president had been unaware of Manafort's client list but held that Manafort had not acted in such a way that would have been problematic, had Trump known.

"The president was not aware of Paul's clients from the last decade, no. What else don't we know? Where he went to school, what grades he got, who he played with in the sandbox?" Spicer said. "To talk about somebody who had a client from 10 years ago, with clients from around the world. I don't know what he got paid to do."

"There is no suggestion that he did anything improper, so to suggest that the president knew who his clients were from a decade ago is insane," he continued. "He was not a government employee, he didn't fill out any paperwork attesting to something, there is nothing that he did suggesting at this point that anything was nefarious. He was hired to do a job, he did it, plain and simple."

Spicer nonetheless continued a days-long effort to minimize Manafort's role in the Trump campaign. On Monday, he told reporters that Manafort had "played a very limited role for a very limited amount of time." On Wednesday, he said Manafort "was hired to count delegates, which he did, and he was successful at it, as he was for [former Presidents] George Herbert Walker Bush, Gerald Ford and [1996 GOP nominee] Bob Dole."

"He was hired to do a job, and he did it, and he did it fine," Spicer said.

But Democrats reacted by saying Manafort's activities on Putin's behalf were an indication that ongoing investigations into ties between people close to Trump and the Kremlin will turn up damning evidence.

"Every day now, it seems, we are learning more about ties between Donald Trump and Russia," said Rep. Steny Hoyer of Maryland, the House minority whip, reiterating Democrats' calls for the investigations into Trump's alleged Russia connections to be handled independently from Congress. "The new information today about Paul Manafort, former Trump campaign manager, only thickens the 'big, gray cloud' hanging over the Trump Administration, as Republican House Intelligence Committee Devin Nunes described it on Monday. It is a cloud spawned from Russia's efforts to undermine our democracy and made darker and more foreboding by some Republicans' attempts to minimize or distract from this deeply concerning affair."

"More evidence that Trump/Russia ties were converging with Russia hacking," said Rep. Eric Swalwell, D-Calif., a member of the Democratic leadership team.

"More evidence emerges that Russia/Trump campaign colluded to elect #FakePresident," said Rep. Hakeem Jeffries of New York, who chairs the House Democrats' communications arm. "What a DISGRACE."

The Russian connection deepens. We need an independent commission to scrutinize Trump's pervasive staff infection. #TrumpRussia https://t.co/WIVBaCuW4p — Rep. Jamie Raskin (@RepRaskin) March 22, 2017

Massachusetts Rep. Jim McGovern suggested Manafort had violated federal law in failing to register as a foreign agent with the Department of Justice.

"That would be a felony," he tweeted. "Every day the mountain of Trump/Russia ties gets bigger."

Top Senate Democrats took the opportunity to renew calls for a delay in the confirmation vote for Trump's Supreme Court nominee, Judge Neil Gorsuch.

On Tuesday, Minority Leader Chuck Schumer of New York called for the vote to be delayed "while this big gray cloud of an FBI investigation hangs over the presidency."

""You can bet if the shoe were on the other foot and a Democratic president was under investigation by the FBI the Republicans would be howling at the moon about filling a Supreme Court seat in such circumstances," he told reporters.

Sen. Elizabeth Warren of Massachusetts agreed.

"Lifetime court appointments can wait," she said.

But is the Senate really going to pretend there's no cloud over @realDonaldTrump & move on w/ the Gorsuch nomination like things are normal? — Elizabeth Warren (@SenWarren) March 21, 2017

Manafort was hired to run the Trump campaign's delegate strategy in March 2016 and was promoted to campaign chairman amid a broader staff shakeup in June. He resigned from the campaign in August, after Ukrainian anti-corruption officials revealed the discovery of a so-called "black ledger" that included Manafort as the recipient of 22 payments totalling $12.7 million in under-the-table cash payments between 2007 and 2012.