U.S. President George Bush has defended his decision to invade Iraq in an interview with the Observer newspaper and downplayed differences in strategy with U.K. Prime Minister Gordon Brown.

In what was seen as a slight to  the British PM, who is expected to announce a full withdrawal of British troops before the end of the year, the president said there "should be no definitive timetable" for withdrawing troops out of Iraq.

Bush added he hoped the prime minister would:

"listen to our commanders, to make sure that the sacrifices that have gone forward won't be unravelled by drawdowns that may not be warranted".

The soon-to-be-released memoirs by former White House press secretary Scott McClellan have caused a stir amongst Bush administration insiders and the Washington press corps.

Some, like former presidential adviser and feared political operative Karl Rove, have scrambled to limit the fallout from the apparent defection of one of the President's Texas inner circle. The political operative has accused him of grandstanding in order to sell a book.

Other Washington insiders have described McClellan's book as a desperate attempt to restore some credibility after allegedly being forced to deliver the administration's spin to the nation on a variety of important issues during his three year tenure from July 17, 2003 to April 26, 2006.