Washington: Democrat Hillary Clinton shuffled her campaign staff's leadership on Sunday ahead of this week's US presidential nominating contests.

Clinton replaced her campaign manager after a string of losses on Saturday.

Her main rival, Barack Obama, won in Maine after easy victories on Saturday in Louisiana, Nebraska and Washington state.

Clinton and Obama are about even in pledged delegates but both are well short of the 2,025 needed to win the Democratic nomination.

Republican John McCain lost two of three state contests on Saturday but got a vote of confidence from President George W. Bush on Sunday.

Former Arkansas Gov. Mike Huckabee beat McCain in Louisiana and Kansas and ran a very close second in Washington state.