White House Chief of Staff Andrew Card is to resign, it emerged this afternoon.
Mr Card will depart the White House on April 14th and will be replaced by budget director Josh Bolten, a senior US government official said today.
President Bush will make the announcement in the Oval Office at 8.30am (2.30 Irish time.
The official, who asked not to be identified, said Mr Card came to Mr Bush about three weeks ago and offered his resignation and after a number of discussions the president accepted it over the weekend at the Camp David presidential retreat.
Mr Card has been chief of staff since Mr Bush took over the presidency in January 2001, far surpassing how long most White House chiefs of staff serve and leading to accusations from some of Bush's Republican allies that the White House was tired.
The senior administration official said Mr Bolten "knows how this White House operates," and is very well respected. He said a smooth transition was expected.
The official said Mr Card felt change was necessary after his lengthy tenure. "It is something he initiated," the official said.