Campaign aides for US Democratic presidential candidate Senator Hillary Clinton of New York set new bar for the nomination race Friday, hinting her rival Barack Obama needs to win all four contests on March 4 to claim victory.

Previously, Bill Clinton, a former US president and husband of Hillary Clinton, had said if his wife doesn't win both the Ohio and Texas primaries, the two big states in March four contests, she won't be the Democratic presidential nominee.

However, in a conference call with reporters on Friday afternoon, Clinton's campaign spokesman Howard Wolfson said if Obama, a senator from Illinois, doesn't win all four states on March 4, "it says something profound about Democrats' unease" with him.

Both Clinton and Obama are focusing on March 4, when Rhode Island, Vermont, Ohio and Texas will hold primaries.

Obama has won the last 11 primaries or caucuses, leading Clinton in many national polls and edging slightly ahead in most news organizations' counts of delegates to the Democratic National Convention.

(Xinhua News Agency March 1, 2008)