FBI officials seized a document on a foreign government's military defences, including its nuclear capabilities, during a raid of Donald Trump's Florida home, it is reported.
Military information on the foreign country, that was not named in the report by the Washington Post, goes against the claim from Mr Trump's defence lawyers that the documents he held were harmless.
The FBI searched Donald Trump’s Mar-a-Lago resort last month as they believed he was concealing classified documents.
Prosecutors sought a search warrant for the former US president’s Florida estate after claiming to have obtained evidence that top-secret documents were hidden there, court filings by the Department of Justice (DoJ) show.
FBI agents raided the property on August 8 after months of negotiation with the former president’s team as they suspected that “government records were likely concealed” from prosecutors.
More than 320 classified documents have been recovered from Mar-a-Lago.
Mr Trump faces a criminal investigation for illegal removal of government records and possible charges of obstruction of justice and violation of the Espionage Act.
The former president pushed an "incomplete and inaccurate narrative" in his recent court filings about the Mar-a-Lago search, the Justice Department said.
This was partly based on prosecutors believing that Mr Trump’s lawyers had deliberately misled the government by claiming there was no more classified material at the Florida estate as they handed back some files in June.
A federal judge on Sunday granted Mr Trump's request for a "special master" to review documents seized from his Mar-a-Lago resort, including to determine if some may be protected by executive privilege.
This privilege is the legal principle that allows certain White House records to be shielded from lawmakers and the courts, in order for presidents to get candid advice on major decisions.
Mr Trump repeatedly asserted the privilege as president in attempts to block records and testimony from Democrats' congressional investigations, including in the first impeachment inquiry of his presidency. No court ruled on the merits of Mr Trump's executive privilege claims while he was in office.
Presidents can also waive the privilege, as President Joe Biden did in response to a request for White House records sought by the congressional committee investigating the January 6, 2021, riots at the US Capitol building by Mr Trump supporters.
