Washington: Hillary Clinton endorsed Barack Obama as the Democratic US presidential candidate on Saturday, ending her own historic White House bid less than a week after he secured enough support to win the nomination.

Clinton's endorsement of Obama in a Washington speech was the first step in efforts to reunite the Democratic Party after a divisive five-month nominating battle. "Today, as I suspend my campaign, I congratulate him," Clinton told about 2,000 cheering supporters at the National Building Museum in Washington.

Her husband, former President Bill Clinton, and her daughter, Chelsea, stood to the side of the stage.

"I endorse him and I throw my full support behind him," she said of Obama. Obama will be crowned the Democratic nominee at the party's August nominating convention and will face Republican John McCain in November to choose a successor to President George W. Bush.