US President Joe Biden has blocked the release of audio recordings of his interviews from the investigation into his handling of classified files.

A letter from the justice department to Republicans in Congress said Mr Biden had asserted executive privilege.

Republicans had demanded the release of the president’s interviews with Special Counsel Robert Hur.

Mr Hur’s explosive report was released in February and it called Mr Biden’s age and memory into question.

He declined to pursue a criminal case against the president, but wrote in his report that Mr Biden would likely be viewed as a “well-meaning, elderly man with a poor memory”.

That prompted a strong response from the president, who said: “I know what the hell I’m doing. I don’t need his recommendation”.

On Thursday, the justice department said in a letter to the chairmen of the House of Representatives Judiciary and Oversight committees that the recordings would not be released.

It said executive privilege would be invoked, which is a legal doctrine that shields some executive branch records from being made public.

US Attorney General Merrick Garland, who leads the department, also criticised “a series of unprecedented and frankly, unfounded attacks” on the justice department from House Republicans.

Mr Garland is likely to be held in contempt of Congress over the move.

He told Mr Biden in a letter on Wednesday that legal counsel had determined the tapes “fall within the scope of executive privilege” – clearing the deck for the White House to withhold their release.

Mr Garland noted that the president had fully co-operated with the criminal investigation and sat voluntarily for the five-hour interview with Mr Hur’s team.

Mr Biden confirmed he was blocking the release of the tapes in a separate letter from his White House counsel to the committee chairmen on Thursday morning.

“The absence of a legitimate need for the audio recordings lays bare your likely goal – to chop them up, distort them, and use them for partisan political purposes,” it said.

The release of Mr Hur’s report came after a year-long inquiry into how Mr Biden allegedly mishandled classified documents after leaving the vice-presidency in 2017.

It said the president was unable to recall details relevant to the investigation during his interview.

The special counsel added that Mr Biden had struggled to recall milestones in his own life, including the years of his vice-presidency and when his oldest son had died.

Republicans claimed the report highlighted voter concerns about his age and lucidity.

Kamala Harris, the vice-president, said Mr Hur’s report was “clearly politically motivated”.

Mr Hur defended his report as “necessary, accurate and fair” during a congressional hearing a month after its release.

The justice department has since provided full transcripts of the special counsel’s interviews as well as other relevant documents to Republicans in the House of Representatives.

James Comer, the Republican chairman of the House oversight committee, has said the refusal to release the recordings was “curious”.

“Why shouldn’t the American people be able to hear the actual audio of his answers?” Mr Comer wrote in a statement last month.

The judiciary and oversight committees will consider contempt resolutions against Mr Garland later on Thursday. If they advance out of the two committees, it will be brought to a vote before the full House.

Republicans currently control the chamber by a single seat and it is unclear if they have the votes to hold Mr Garland in contempt, referring him for possible prosecution.

If Mr Garland is held in contempt, he will join his predecessors Bill Barr, of the Donald Trump administration, and Eric Holder, of the Barack Obama administration, in facing that fate.

Neither man faced criminal charges from their own justice departments.