Republican leaders of two committees in the U.S. House of Representatives launched an investigation on Tuesday into the purchase by a Russian firm several years ago of a Canadian-based company that owned some 20 per cent of U.S. uranium supplies.

Republican lawmakers say they want to know whether the 2010 transaction involving Rosatom and Uranium One, which has headquarters in Toronto, was fully investigated by the FBI and other agencies before it was approved by a panel that oversees foreign investment in U.S. strategic assets.

"We're not going to jump to any conclusions at this time,"said Devin Nunes, a Republican from California. "But one of the things that you know that we're concerned about is whether or not there was an FBI investigation. Was there a [Department of Justice] investigation? And if so, why was Congress not informed of this matter?"

Some Republicans have claimed that Hillary Clinton's State Department approved the deal after her husband's charitable foundation received a $145-million US donation, but the State Department controls only one seat on the panel that approved the transaction and the New York Times reported two years ago that she did not participate in the decision.

Canadian businessman and philanthropist Frank Giustra, left, is shown at a 2007 event in New York with former U.S. president Bill Clinton. (Frank Franklin II/Associated Press)

The accusations gained steam in right-wing media circles after the 2015 publication of the book Clinton Cash: The Untold Story of How and Why Foreign Governments and Businesses Helped Make Bill and Hillary Rich.

Frank Giustra, the Vancouver-based mining executive who donated $31 million to Clinton Foundation initiatives around the world and pledged millions more, said in a statement at the time "there is not one shred of evidence" that any of the events were connected. Giustra pointed to the fact he sold his stake in Uranium One three years before the Russia deal, and about 18 months before Clinton became secretary of state.

More recently, Giustra tweeted a link to a Harvard study regarding last year's election coverage, saying that Trump adviser Steve Bannon, Breitbart.com, Clinton Cash author Peter Scheitzer and Fox News helped propagate a story that sowed doubts about Clinton in election voters' minds.

Partisanship, Propaganda, and Disinformation:Media and the 2016 U.S. Presidential Election <a href="https://twitter.com/mcuban?ref_src=twsrc%5Etfw">@mcuban</a> <a href="https://twitter.com/peterschweizer?ref_src=twsrc%5Etfw">@peterschweizer</a> <a href="https://t.co/jpZkJ9q2Ay">https://t.co/jpZkJ9q2Ay</a> —@Frank_Giustra

Bannon ,Schweitzer Breitbart, Fox,framed a story so attractive for mainstream media to cover,caused voters to doubt Clinton’s integrity." —@Frank_Giustra

Canadian mining executive Ian Telfer, who was chairman of Uranium One at the time of the Russia deal, said his pledge to the Clinton Foundation of over $2 million was made in 2008.

Hillary Clinton said in an interview with C-SPAN last week that the renewed interest in the deal is "the same baloney they've been peddling for years," referring to the Republicans.

She stated her belief the Republicans were looking to distract from the various investigations that are taking place into dealings between members of Donald Trump's campaign and transition teams and Russian officials.

Nunes himself came under heavy criticism, and was forced to step down as co-chair of a House probe into Russia after allegations he mishandled classified information.

Trump himself has brought up the spectre of the deal on the campaign trail and as recently as five days ago, claiming the mainstream media hasn't properly covered the transaction.

When asked about the investigation announcement at a White House briefing, Press Secretary Sarah Huckabee Sanders said it was "a step in the right direction."

She said she had yet to talk to Trump about the latest development.