A leading Republican was recorded last year saying he believed US President Donald Trump was on Russian President Vladimir Putin's payroll.
"There's two people I think Putin pays: Rohrabacher and Trump," House Majority leader Kevin McCarthy said, the Washington Post reports.
Dana Rohrabacher, who like Mr Trump is a Republican, is a long-time friend of Mr Putin. On being told by the Post about Mr McCarthy's comments, Mr Rohrabacher said Mr McCarthy was "joking".
The conversation on the tape is halted by House Speaker Paul Ryan, who "immediately interjected, stopping the conversation from further exploring Mr McCarthy's assertion, and swore the Republicans present to secrecy", the Post reports.
"No leaks... this is how we know we're a real family here," Mr Ryan says.
"What's said in the family, stays in the family."
Mr McCarthy is heard saying "swear to God" in defence of his claims, after others present laughed.
"It's true that Majority Leader McCarthy said that he thought candidate Trump was on the Kremlin's payroll," confirmed Evan McMullin, the former independent candidate for President who was at the meeting.
"Speaker Ryan was concerned about that leaking."
The tape was made in June last year, before WikiLeaks started releasing Hillary Clinton's emails its believed were supplied by Russian intelligence services, in order to tip the election in Mr Trump's favour.
The Trump campaign is currently being investigated over its alleged ties to Russia. A special counsel has been formed to take over the FBI-led investigation, after Mr Trump fired FBI director James Comey last week.
The White House was not informed of Deputy Attorney General Rod Rosenstein's decision to form a special counsel until after it had been made, and was only given a half-hour's notice before it was made public.
A spokesperson for Mr Rohrabacher said he backs working with Russia to fight radical Islam.
Mr Trump earlier this week admitted giving classified information to the Russian Foreign Minister, saying it was his right to do so as President, and to help "Russia to greatly step up their fight against ISIS & terrorism".