Barack Obama will publicly disclose his vice-presidential choice in the coming days, though the Democrat is keeping most aides who are preparing for the announcement in the dark and giving away nothing to voters as he campaigns.

The Illinois senator has staffers in place to aid his prospective running mate, including more than a dozen seasoned operatives who have set up a shop in a section of the campaign's Chicago headquarters.

Obama was believed to have narrowed his list to Virginia Governor Tim Kaine, Delaware Senator Joe Biden, Indiana Senator Evan Bayh and Kansas Governor Kathleen Sebelius. While it seemed increasingly unlikely that he would choose his vanquished rival, New York Senator Hillary Rodham Clinton, some Democrats speculated on Monday that he could pull a surprise and pick her.