Barack Obama won the support of some of the biggest backers of his former rival Hillary Clinton today as she finally signalled that the end of her bid for the Democratic nomination was near.
The former first lady sent an email to supporters which said she would hold a meeting on Saturday where she would speak “about how together we can rally the party behind Senator Obama”.
She went on: “The stakes are too high and the task before us too important to do otherwise.”
Mr Obama will make history as the first black presidential nominee of a major US party after he clinched the nomination on Tuesday, the final day of one of the closest and most expensive primary seasons in memory.
He will now face Republican John McCain in November’s general election to decide who will be the 44th president of the United States.
Several of Mrs Clinton’s supporters have encouraged Mr Obama to consider her as a running mate on a so-called “dream ticket”.
But the 46-year-old Illinois senator said he was in no hurry to make a decision and added that former first daughter Caroline Kennedy would help lead the search for a potential vice president.
“We’re not going to be rushed into it. I don’t think Senator Clinton expects a quick decision and I don’t even know that she’s necessarily interested in that,” he told US TV network NBC.
Representatives Gregory Meeks and Edolphus Towns backed Mr Obama and called for party unity.
In a statement, they said: “We stand firmly in his corner and are ready to help him continue to make history on behalf of the American people.”
Other colleagues of the 60-year-old New York senator were also preparing a group endorsement of Mr Obama.
Clinton communications director Howard Wolfson confirmed Mrs Clinton would express her support for Mr Obama at the event in Washington, DC, on Saturday as she thanked her supporters.
She will also urge once-warring Democrats to focus on the general election campaign in a bid to defeat former Vietnam prisoner of war and Arizona senator Mr McCain.
Campaign aides said Mrs Clinton was also exploring options to retain her delegates and promote her issues, including her signature call for universal health care.
The moves to end her campaign came after she was urged to clear the way for Mr Obama in a telephone call with impatient congressional supporters, including New York representative Charles Rangel, a longtime political patron.
“The quicker we proved that we were committed to Senator Obama, then the better for all of us,” Mr Rangel told CBS’ Early Show.
He said Mr Obama and Mrs Clinton needed each other.
Yesterday, Mr Obama praised the former first lady, criticised Republican John McCain and also tried to reassure Jewish leaders over his foreign policy as both he and Mrs Clinton spoke at a conference of the American Israel Public Affairs Committee (Aipac) in Washington DC.
He said that rumours and suggestions that he was unfriendly to Israel and to Jewish interests were unfounded.
To applause, he said: “I will never compromise when it comes to Israel’s security.”
And he pledged to use “all elements of American power” to eliminate Iran’s nuclear threat.
In her own speech immediately after Mr Obama had finished, Mrs Clinton said: “Let me be very clear, I know that Senator Obama will be a good friend to Israel.”
She went on: “And let me underscore, I believe we need a Democrat in the White House next January.”
Some US talk show hosts have suggested that disgruntled Clinton supporters ought to cast their vote for Mr McCain, rather than Mr Obama, in the general election.
The former first lady told the audience of around 7,000 people: “I know Senator Obama understands what is at stake here.
“It has been an honour to contest these primaries with him. It is an honour to call him my friend.”
She went on: “I know that Senator Obama shares my view that the next president must be ready to say to the world, ’America’s position is unchanging, our resolve unyielding, our stance non-negotiable’.
“The United States stands with Israel, now and forever.”
She added that the next president would inherit “grave problems” and criticised both President George Bush and Mr McCain as she said: “America needs a new beginning in our foreign policy, to make our country stronger and frankly, to make our position in the world more credible, to give us our strategic leverage back that we have lost over the last seven years.”