SPRINGFIELD, Ill. — Barack Obama's newly minted running mate will be hitting the trail with the Democratic hopeful Saturday.

A senior Obama adviser told The Associated Press on condition of anonymity Tuesday that Obama and his v.p. choice will appear together in front of the former state Capitol in Illinois where Abraham Lincoln once served.

The last time Obama appeared there, early in 2007, he announced he was running for president.

The disclosure narrowed the window for Obama to reveal his running mate. The campaign says the announcement will come in a cell-phone text message to supporters.