WASHINGTON (CNN) -- Sen. Barack Obama and Sen. Hillary Clinton met late Thursday in Washington, D.C. -- their first meeting since Obama became the presumptive Democratic presidential nominee.
"Sen. Clinton and Sen. Obama met tonight and had a productive discussion about the important work that needs to be done to succeed in November," a joint statement from the two sides said.
CNN's Candy Crowley confirmed that the two met to discuss plans for "bringing the campaigns together in unity for the party."
Earlier, reporters on Obama's press plane learned that the presumed Democratic nominee for president was not aboard when it departed Virginia, where he had been campaigning. Aides said staff members "scheduled him some meetings" in Washington.
The meeting originally was believed to be at Clinton's D.C. home, but sources later said the two met elsewhere in Washington.
A group that is urging Obama to select Clinton as his running mate praised the meeting. "We are thrilled to hear that Senators Obama and Clinton are meeting already," said a statement from VoteBoth. "We hope that Thursday night's conversation is a step toward an Obama-Clinton ticket that will unify the party."
Also Thursday, Clinton thanked supporters in an e-mail and pledged to help Obama capture the White House after eight years of Republican control. Clinton also plans to thank supporters in person at a Washington event Saturday.
"I have said throughout the campaign that I would strongly support Sen. Obama if he were the Democratic Party's nominee, and I intend to deliver on that promise," the e-mail read.
"This has been a long and hard-fought campaign, but as I have always said, my differences with Sen. Obama are small compared to the differences we have with Sen. [John] McCain and the Republicans." Read Clinton's message to supporters (PDF)
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Democrats nationwide have coalesced around Obama since he received enough delegates to win the nomination Tuesday evening.
Top Democrats from Clinton's home state of New York plan to endorse the Illinois senator, congressional staffers and Obama campaign insiders said.
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On Friday, Democratic leaders in New York, including Gov. David Paterson, state legislators and city council members, plan to endorse Obama at a 1 p.m. news conference at New York's City Hall, the sources said.
Obama earned enough delegates Tuesday to clinch the nomination, but Clinton did not concede defeat that night. Instead, she asked supporters to visit her Web site and give her advice on how to proceed.
Since then, Clinton supporters have stepped up efforts to get her the vice presidential slot.
Billionaire Bob Johnson, founder of Black Entertainment Television, said he plans to ask the Congressional Black Caucus to urge Obama to offer Clinton the vice presidential slot. And Rep. Charles Rangel, D-New York, said that putting Clinton on the ticket would help unify the party.
"A lot of her supporters are still brokenhearted, but if we see that her candidacy is treated with respect and that we're going to have one ticket -- the Obama/Clinton ticket -- I think that would bring us together like no other political incentive," he said. Watch what Clinton wants »
Both campaigns deny that discussions on the subject have begun.
Clinton and Obama spoke by phone about two hours after Obama claimed victory in the nominating fight. They spoke again on Wednesday, at the annual conference of AIPAC, an influential pro-Israel lobbying group.
In her remarks to the group, Clinton heaped effusive praise on Obama.
"Let me be very clear," Clinton said. "I know that Sen. Obama will be a good friend to Israel. I know that Sen. 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 nonnegotiable."
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Clinton looked toward the general election in the e-mail Thursday.
"I will be speaking on Saturday about how together we can rally the party behind Senator Obama," the message said. "The stakes are too high and the task before us too important to do otherwise."
She acknowledged receiving support throughout her campaign, including "hundreds of thousands of messages" in the last few days.
"I can never possibly express my gratitude," the message said, "so let me say simply, 'Thank you.' "
CNN's Candy Crowley contributed to this report