US President Joe Biden has been questioned as part of an investigation into the handling of classified documents found at his home and former private office, the White House said Monday.
A furor over the secret papers dating from Biden's time as vice president prompted the US attorney general to name an independent prosecutor to carry out a probe in January.
"The president has been interviewed as part of the investigation being led by Special Counsel Robert Hur," the White House said in a statement.
It said the "voluntary interview" with the 80-year-old Democratic president took place at the White House on Sunday and Monday.
"As we have said from the beginning, the president and the White House are cooperating with this investigation," it said.
The White House said it was also "being as transparent as we can consistent with protecting and preserving the integrity of the investigation."
It referred further questions to the Justice Department.
The probe involves documents found in the possession of Biden, who was vice president under Barack Obama when the papers were removed from the White House.
Records were first unearthed in a private think tank office where the president used to work in Washington in November 2022.
More documents were found in the president's Wilmington, Delaware garage on December 20 and in his home library on January 12.
Former president Donald Trump, Biden's likely Republican opponent in the 2024 election, separately faces trial over the alleged mishandling of classified documents after leaving office.
The special counsel in that case, Jack Smith, says Trump allegedly took classified documents to his Mar-A-Lago estate in Florida and refused to return them.
He pleaded not guilty in June to charges of unlawfully retaining national defense information, conspiracy to obstruct justice and making false statements.
The prosecutor in that case has asked for a 2024 trial, one of a number that Trump faces on various charges which include trying to overturn the results of the 2020 election, which he lost to Biden.
Republicans have been trying to draw parallels between the Trump and Biden document cases.
Biden's son Hunter meanwhile faces yet another special counsel probe into tax fraud and gun possession.
