President Joe Biden was interrogated as part of an investigation into his handling of classified documents following his 2017 resignation as vice president.

Mr. Biden voluntarily met with Special Counsel Robert Hur for two days at the White House, according to officials.

After a separate investigation into the secret documents discovered in Donald Trump's home, Mr. Hur was appointed. Mr. Biden is not facing any criminal charges. It is not uncommon for investigators to interrogate presidents.

Mr. Biden's spokesman, Ian Sams, stated that Mr. Hur, who was selected by US Attorney General Merrick Garland to oversee the investigation, personally conducted it. He added that the interview ended on Monday evening.

Mr. Sams informed sources that the President and White House are cooperating with this investigation.

Appropriately, they have provided relevant updates to the public, being as transparent as possible while protecting and preserving the investigation's integrity. 

He stated that they would refer other questions to the Justice Department at this time. 

The documents were discovered by Mr. Biden's associates in an office he used after leaving the vice presidency and prior to launching his presidential campaign.

The first accumulation of classified documents was discovered on November 2 at the Washington, D.C.-based think tank the president founded, the Penn Biden Center.

On 20 December, a second bundle of records was discovered in the garage of his Wilmington home, and on 12 January, another document was discovered in the house's storage area, according to his attorneys at the time.

After discovering the documents, according to the president, his staff promptly forwarded them to the National Archives and the Justice Department. It is unclear why Mr. Biden retained them.

Under the Presidential Records Act, White House records are to be transferred to the National Archives, where they can be securely preserved, upon the conclusion of an administration. Mr. Biden has previously stated that he was unaware that the documents existed.

Authorities have not disclosed the nature of the files. The subject matter of classified documents can range from relatively mundane to highly classified.

However, sources mentioned earlier that the first batch of 10 classified documents contained briefing materials on foreign countries, including Ukraine, Iran, and the United Kingdom, from Mr. Biden's tenure as vice president.

These documents were jumbled in with other non-classified documents, including information about the 2015 funeral of Beau Biden, the president's son.

It was also reported that some of the documents were classified at the highest level, top secret.

The interview took place amid dramatic tensions in the Middle East and had been scheduled months in advance, according to a White House official quoted by the New York Times.

The conclusion of the interview may indicate that the investigation is nearing its conclusion. Mr. Hur's staff has not yet determined whether or not to press charges against Mr. Biden.

In a separate investigation with a broader scope, Special Counsel Jack Smith is bringing charges against Mr. Trump for allegedly retaining highly sensitive government documents at his Florida residence and golf resort after leaving office.