Donald Trump's long-time attorney, Michael Cohen, secretly recorded a conversation two months before the 2016 presidential election in which the then presidential candidate discussed making payments related to a Playboy model, US media reported on Friday.
The recording was seized by the FBI during raids of Mr Cohen’s home and offices in April.
The development comes amid signs that Mr Cohen could be open to co-operate with investigators.
The existence of the recording was confirmed by the president’s lawyer, Rudy Giuliani, on Friday, though he claimed it did not impugn the president.
The recording reportedly reveals Mr Trump discussing a plan to buy the rights to a story by Playboy model Karen McDougal from AMI, the parent company of the National Enquirer. Ms McDougal claims she had a 10-month affair with the businessman. She then sold her story to AMI for $150,000 (€130,000) but it was not published, under a policy called “catch and kill” which prevents certain stories being published. Mr Trump is seen to be close to AMI and the National Enquirer.
Mr Trump has denied the affair with Ms McDougal and any knowledge of a payment.
Mr Cohen was arrested by prosecutors in April for possible bank and tax charges, though he has not been charged. Prosecutors are focusing on Mr Trump’s alleged affairs with two women – adult film star Stormy Daniels and Playboy model Karen McDougal. Any payments by the president to the women could be in violation of federal election law.
The development comes as the fallout from Monday's summit between the US president and Vladimir Putin continued on Friday.
Mr Trump's decision to invite Mr Putin to Washington in the autumn – announced on Twitter by press secretary Sarah Huckabee Sanders on Thursday – caught many of his own advisers unawares. This included director of national intelligence Dan Coats, who was informed of the announcement during a live interview in Colorado.
“Say that again?” he said to laughs when he was told of the news during the interview, adding with a smile: “that’s gonna be special”.
His comments have sparked speculation about his long-time future in the Trump administration. Mr Coats, a former senator who was tapped by Mr Trump for the top intelligence position, issued a stern statement on Monday after Mr Trump's widely panned press conference with the Russian leader in Helsinki. Though he did not mention Mr Trump by name, the statement stood by the findings of the US intelligence community, which believe that Russia interfered in the election.
“We have been clear in our assessments of Russian meddling in the 2016 election and their ongoing, pervasive efforts to undermine our democracy, and we will continue to provide unvarnished and objective intelligence in support of our national security,” the statement said.
Mr Coats defended his decision to issue the statement. “It was important to take that stand on behalf of the intelligence community and on behalf of the American people,” he said during the interview on Thursday.
Mr Coats also said he did not know what happened during Monday’s meeting between Mr Trump and Mr Putin.
Mr Trump departed for his golf club in New Jersey on Friday afternoon for the weekend with the first lady, Melania Trump, but did not answer shouted questions by reporters.
Earlier in the day, Mr Trump accused China and the European Union of currency manipulation. "China, the European Union and others have been manipulating their currencies and interest rates lower, while the US is raising rates while the dollar gets stronger and stronger with each passing day – taking away our big competitive edge. As usual, not a level playing field," he tweeted.