Citing sources, the network said presumptive Democratic presidential nominee Barack Obama personally invited Clinton to speak at the convention. Plans call for the former president to address the convention Wednesday, Aug. 28, prior to a speech by the Democrats' running mate.

The report came as aides to Obama and his main rival for the nomination, New York Sen. Hillary Clinton, issued a statement saying they were working together to ensure victory in the presidential election, even as Clinton supporters urge her to have her name placed in nomination at the convention. Hillary Clinton had suggested during a California fundraiser she was weighing her options, Politico reported Thursday.

"I happen to believe that we will come out stronger if people feel that their voices were heard and their views were respected. I think that is a very big part of how we actually come out unified," ABC News reported Clinton as saying. "No decisions have been made. And so we are trying to work all this through with the (Democratic National Convention) and with the Obama campaign."

The Obama and Clinton camps, in an e-mail message, downplayed possible conflict, Politico said.

"We are working together to make sure the fall campaign and the convention are a success. At the Democratic Convention, we will ensure that the voices of everyone who participated in this historic process are respected and our party will be fully unified heading into the November election," the statement said.