Former US president Donald Trump reportedly kept more than 300 classified documents in his Mar-a-Lago home after he left office, The New York Times reported, with other outlets saying on Tuesday that he may have held hundreds more.
The New York Times said on Monday that Mr Trump's team handed some documents over to the US government in January and June, and the rest were obtained during the FBI search of his Palm Beach resort.
The newspaper reported that US authorities still are not sure if all sensitive documents Mr Trump may have taken from the White House have been retrieved.
Reuters and ABC News reported on Tuesday that the National Archives had discovered Mr Trump may have kept more than 700 pages of classified documents at his home, according to a May letter the records agency sent to the Republican former president's lawyer that was made public by a Trump ally.
An unsealed FBI warrant for the August 8 search showed that the former president is being investigated for espionage, obstruction of justice and the mishandling of sensitive records.
On Monday, lawyers for former US president Donald Trump asked a federal judge to prevent the FBI from continuing to review documents recovered from his Florida estate earlier this month until a “special master” can be appointed.
A special master is a neutral, third-party lawyer given the task of overseeing the review of the gathered evidence.
The lawyers asserted in a court filing — their first since the FBI search of Mar-a-Lago two weeks ago — that the documents taken from the residence were “presumptively” covered by executive privilege.
“This matter has captured the attention of the American public,” the lawyers wrote.
“Merely ‘adequate’ safeguards are not acceptable when the matter at hand involves not only the constitutional rights of President Trump, but also the presumption of executive privilege.”
FBI agents carted away about 20 boxes containing 11 sets of classified documents — some of them labelled “top secret” — following the August 8 search.
Mr Trump’s passports, which were taken during the raid, have already been returned and it is unclear what documents he claims are protected by executive privilege.
He has made a variety of public claims explaining that he did nothing wrong in taking the documents from the White House when he left office, including that he had made a “standing order” to declassify records.
Evidence has not been provided to back his claims of declassifying the documents found at Mar-a-Lago.
Federal investigations can involve separate “filter” or “taint” teams to identify and return privileged information. Exposing primary prosecutors or agents to this material could disqualify them or place a future prosecution in legal jeopardy.
The Justice Department also faces a Thursday deadline to propose redactions for the FBI affidavit that was used to justify the search warrant.
A judge ruled the affidavit should be partially unsealed, rejecting the government’s claim that such a move would put the ongoing probe at risk.
News agencies contributed to this report