"They did meet tonight," Robert Gibbs, Obama's communications director, told reporters in response to media reports about the session.

Gibbs said reports they met at Clinton's home in Washington were incorrect. He declined to disclose the location or details of what they discussed.

He spoke on the Obama campaign plane traveling to Chicago. Obama had been scheduled to fly back to that city on Thursday evening after a rally in northern Virginia but stayed behind for the meeting with Clinton, shedding his campaign plane and the traveling press corps.

CNN reported the Obama-Clinton session was "a small meeting" with perhaps just the two senators and a few aides in attendance.

The New York Times said the meeting with Obama was initiated by Clinton after a daylong series of talks between their aides.

There is intense speculation Obama might pick Clinton as his running mate for November's presidential election against Republican John McCain.

Obama has said the process would take time. Clinton, who has expressed an interest in running as vice president, sought to distance herself on Thursday from efforts by supporters to convince Obama to pick her, saying the choice was up to him.

Obama, an Illinois senator, clinched the Democratic nomination on Tuesday. Clinton, a New York senator and former first lady, did not immediately concede but told supporters in a letter she would formally back Obama on Saturday.

Reuters