US President George Bush today invoked executive privilege to deny requests by Congress for testimony from two former aides about the firings of US prosecutors.

US PRESIDENT George W Bush, moving toward a constitutional showdown with Congress, asserted executive privilege yesterday and rejected lawmakers’ demands for documents that could shed light on the firings of federal prosecutors.

A United States Senate panel, following the House of Representatives' lead, has authorised subpoenas for White House political adviser Karl Rove and other top aides involved in the sacking of federal prosecutors.

Former top FBI official Mark Felt was branded an American hero by his family after unmasking himself as the Deep Throat source who helped bring down President Richard Nixon in the Watergate scandal.