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…