Trump, who was friends with Epstein before becoming president but had a falling out with the financier years before his death, has denied giving him a letter that appears in a birthday book for Epstein with the sketch of a woman's body and a note about secrets.
Democrats in the US House of Representatives on Monday released the letter, written more than 20 years ago, to the public. The White House quickly denied its authenticity.
Karoline Leavitt, the president's spokeswoman, told reporters on Tuesday the White House would back an analysis of the signature to prove Trump right.
"The president did not write this letter. He did not sign this letter," she said.
The release of the documents has brought renewed attention to an issue that has become a political thorn in the president's side.
Though he has urged his supporters to move on from the topic, appetite for details about Epstein's crimes and who else may have known about them or been involved with him has remained high.
A Reuters/Ipsos poll completed on Tuesday found the US public continues to harbour suspicions about the Epstein case, with 65 per cent of respondents saying the government is hiding information about his 2019 death in prison, which was ruled a suicide, and 72 per cent saying the government is hiding information about the accused sex trafficker's client list. Both figures were up slightly from a similar survey in July.
However, the survey of 1084 adults found a bright spot for Trump: 44 per cent of Republican respondents said they approved of the way he was handling the Epstein matter, up from 35 per cent in July. Overall, only 17 per cent of the public approved of his handling of the issue.
Leavitt accused Democrats of trying to hurt the president by focusing on the Epstein case.
"Republicans in the Trump Department of Justice have done more in terms of transparency when it comes to the Epstein case than any prior administration," she said.
