An audio recording in which Donald Trump appears to acknowledge keeping a classified document after leaving the White House has been obtained by US media.
In the recording, the former president is heard riffling through papers and saying: "This is highly confidential".
It has not been independently verified by the BBC.
Mr Trump has pleaded not guilty to federal charges of mishandling sensitive files.
CNN was the first to publish the roughly two-minute clip, and said it comes from a July 2021 interview that Mr Trump gave with people working on the memoir of his former chief of staff Mark Meadows.
Mr Trump is heard saying "these are the papers" and referring to a document he calls "highly confidential".
It appears to be an audio recording referenced by federal prosecutors in their indictment of the former president.
Prosecutors allege he showed classified documents to people without security clearance on two occasions, including a writer and two members of staff, in one instance in July 2021 at his golf club in New Jersey.
Mr Trump is facing 37 counts of illegally retaining classified documents and obstructing the government's efforts to get them back.
He has denied any wrongdoing and has said that all documents he took with him from the White House were declassified.
During the exchange, released by CNN and the Washington Post on Monday, Mr Trump is heard describing a document that he alleges is about possibly attacking Iran.
"He said that I wanted to attack Iran. Isn't it amazing?" Mr Trump says near the beginning of the clip.
"I have a big pile of papers, this thing just came up. Look," he says.
"See as president I could have declassified it," he says. "Now I can't, you know, but this is still a secret."
In an interview last week with Fox News, Mr Trump denied that he provided secret documents to people unauthorised to view them.
"There was no document. That was a massive amount of papers and everything else talking about Iran and other things," Mr Trump said.