WASHINGTON (Reuters) - An informant whom House Republicans have said could reveal a link between a 2010 sale of U.S. uranium supplies and donations to the Clinton Foundation provided no evidence of that during a four-hour interview with congressional staff last month, Democrats said on Thursday.

FILE PHOTO - Former Secretary of State Hillary Clinton speaks at the annual Hillary Rodham Clinton awards ceremony at Georgetown University in Washington, U.S., February 5, 2018. REUTERS/Aaron P. Bernstein

The informant, lobbyist William D. Campbell, “provided no evidence of a quid pro quo involving Secretary (Hillary) Clinton or the Clinton Foundation and no evidence that Secretary Clinton was involved in, or improperly influenced” the uranium sale, the Democrats said in a five-page summary of the Feb. 7 interview.

Democrats said they were releasing a summary of the session because majority Republicans, who control the panels involved, refused to approve the preparation of a full transcript.

“Mr. Campbell identified no evidence that Secretary Hillary Clinton, President Bill Clinton, or anyone from the Obama Administration took any actions as a result of Russian requests or influence,” the summary says.

At issue is the sale - during Clinton’s tenure as U.S. Secretary of State - of Uranium One, a Canadian company that controlled roughly 20 percent of U.S. uranium supplies, to Russian state-owned nuclear power company Rosatom.

At the time of the sale, Campbell was a confidential source for the Federal Bureau of Investigation in a bribery and kickback probe of the head of a U.S. unit of Rosatom.

Republicans, including President Donald Trump, have pressed for a fresh investigation of the issue, alleging that Clinton orchestrated the sale in return for donations to the Clinton Foundation, and was unduly influenced by Moscow.

Democrats call the charges an effort to distract from ongoing investigations into whether Trump’s campaign colluded with Russia during the 2016 presidential election. The White House and Kremlin deny any collusion.

Campbell’s attorney, Victoria Toensing, did not immediately reply to an email seeking comment about his congressional interview.

Republican Representative Ron DeSantis, in a television interview last October, said the informant, whom he did not name then, “would be able to link” the Uranium One sale to financial gain for Hillary Clinton and her husband, former president Bill Clinton.

A DeSantis spokeswoman did not immediately reply to an email seeking comment.

The Uranium One sale was unanimously approved by the Committee on Foreign Investment in the United States (CFIUS), which comprises representatives of nine U.S. government agencies. When the issue was voted on, the State Department was represented not by Clinton, but by a lower-level official.

Five committees in the U.S. House and Senate previously looked into the issue and found no evidence that Clinton was behind CFIUS’ approval of the deal, according to congressional records.

Campbell was interviewed by Republican and Democratic staffers from the House Oversight and Intelligence committees and the Senate Judiciary Committee.

“We appreciate Mr. Campbell’s service to our country and his willingness to appear before the Committee to answer questions related to our core investigative mission: to determine what the FBI did or did not know at the time CFIUS approved the Uranium One deal, and how we can improve the CFIUS process and agency coordination moving forward,” said House Oversight Committee spokeswoman Amanda Gonzalez in response to a request for comment.

(This version of the story was refiled to correct paragraph 14 to add dropped words “to determine”)