An FBI informant involved in the controversial Uranium One deal has told congressional committees that Moscow paid millions to a U.S. lobbying firm in a bid to influence then-Secretary of State Hillary Clinton by helping former President Bill Clinton’s charities during the Obama administration.

The Hill first reported late Wednesday that informant Douglas Campbell gave a 10-page statement to the Senate Judiciary Committee, House Intelligence Committee and House Oversight and Government Reform Committee, and was interviewed for several hours behind closed doors by committee staff.

In the statement, obtained by Fox News, Campbell said Russian executives told him that Moscow was hiring APCO Worldwide in an effort to influence the Obama administration and Hillary Clinton.

Campbell said Russian nuclear officials “told me at various times that they expected APCO to apply a portion of the $3 million annual lobbying fee it was receiving from the Russians to provide in-kind support for the Clinton’s Global Initiative.”

“The contract called for four payments of $750,000 over twelve months,” Campbell said in the statement. “APCO was expected to give assistance free of charge to the Clinton Global Initiative as part of their effort to create a favorable environment to ensure the Obama administration made affirmative decisions on everything from Uranium One to the US-Russia Civilian Nuclear Cooperation agreement.”

In a statement to Fox News, though, APCO called Campbell's assertion "false and unfounded."

"APCO Worldwide undertook client work on behalf of Tenex in 2010 and 2011. It undertook work for the Clinton Global Initiative from 2008-2016," APCO told Fox News. "These projects were totally separate and unconnected in any way. All APCO’s actions on these two unconnected activities were publicly documented from the outset, legally proper and entirely ethical. Any assertion otherwise is false and unfounded."

Uranium One is a Canadian mining company whose sale to a Russian firm was approved in 2010. The U.S. government was involved because the sale gave the Russians control of part of the U.S. uranium supply. The transaction has faced renewed scrutiny after The Hill reported last year that the FBI had evidence as early as 2009 that Russian operatives used bribes, kickbacks and other dirty tactics to expand Moscow’s atomic energy footprint in the U.S., related to a subsidiary of the same Russian firm.

Republican lawmakers on Capitol Hill want to know how the deal was approved the following year by an inter-agency committee.

The Campbell statement also described an earlier meeting with Russian officials outside Washington where they "boasted about how weak the U.S. government was in giving away uranium business," and referred to then-President Barack Obama "with racial epithets."

Campbell’s attorney Victoria Toensing said her client has reported a “strategic plan” by Russian President Vladimir Putin to “take over the uranium industry.”

“[The Russians] were so confident that they told Mr. Campbell with the Clinton’s help, it was a shoo-in to get CFIUS [The Committee on Foreign Investment in the United States] approval,” Toensing said on “Hannity.” “They were so confident in that that they even had him open up the new office because they were planning on the kind of business they were going to do as soon as CFIUS approved it.”

Toensing told Fox News that Campbell was told by the FBI that Obama was aware of the information.

“He was told that President Obama had it in his daily briefing twice,” Toensing said.

Congressional Republicans have called for further investigation into Uranium One. Attorney General Jeff Sessions last year directed senior federal prosecutors to evaluate “certain issues” requested by Republicans, including Uranium One and alleged dealings related to the Clinton Foundation, leaving the door open for the appointment of another special counsel.

But this week, Democrats have charged that Campbell’s statements and the Republican interest in them is a tactic to distract from the larger Russia probe clouding the Trump administration.

Democrats have accused Republicans of making “wild claims” against Clinton.

“Republicans have been talking directly to this individual while refusing to grant Democratic members access, despite multiple requests,” Ranking Members of the House oversight and intelligence committees, Elijah Cummings, D-Md., and Adam Schiff, D-Calif., said in a statement. “During this same time period, Republicans have been making wild and unsubstantiated allegations against Secretary Clinton on national television based on this individual’s information.”

Cummings and Schiff said that the Justice Department provided them with a “detailed briefing” that “directly contradicts these Republican allegations.”

Cummings and Schiff said Campbell never provided any evidence or made allegations regarding Clinton or the Clinton Foundation in any of their interactions with him.

The ranking members claimed that the Justice Department stated that “at no point did [the individual] provide any allegation of corruption, illegality, or impropriety on Clinton, the Clinton Foundation, President Clinton, the Uranium One deal, or CFIUS,” and said there were “no allegations of impropriety or illegality” regarding Clinton in the documents they reviewed.

The Justice Department told Fox News they would not confirm whether the Schiff-Cummings characterization was accurate.

Toensing disputed the Democrats' claims, calling Schiff "disingenuous."

The Clinton Global Initiative did not immediately respond to Fox News’ request for comment.

Hillary Clinton spokesman Nick Merrill panned the informant claims, likening them to the controversial "Nunes memo" on alleged surveillance abuse released last week and newly released text messages between anti-Trump FBI officials.

"Just this week the committee made clear that this secret informant charade was just that, a charade. Along with the widely debunked text-message-gate and Nunes' embarrassing memo episode, we have a trifecta of GOP-manufactured scandals designed to distract from their own President's problems and the threat to democracy he poses," he said in a statement.

Fox News’ Griff Jenkins contributed to this report.