Clinton, Obama battle in Indiana, North Carolina primaries

Obama began the day with 1,745.5 delegates, to 1,608 for Clinton, out of 2,025 needed for the nomination.

Both races were dominated in their final days by Clinton's call for a summertime suspension of the federal gasoline tax, an issue that she created after scoring a victory in the Pennsylvania primary two weeks ago.

Obama ridiculed the proposal as a stunt that would cost jobs, not the break for consumers she claimed. The two rivals dug in, devoting personal campaign time and television commercials to the issue.

Indiana had 72 delegates at stake, and Clinton projected confidence about the results by arranging a primary-night appearance in Indianapolis.

North Carolina had 115 delegates at stake, and Obama countered with a rally in Raleigh.

Clinton, who appeared at the Indianapolis Motor Speedway Tuesday with racer Sarah Fisher, wouldn't make a prediction about the outcome of the primaries.

"Every race is filed with the unexpected. You never know what's going to happen from day to day," said Clinton. "I never make predictions."

Clinton posed for pictures with the racer's pit crew in its garage and Fisher talked about parts of the powder blue car.

"This may be the technology of the future," Clinton said, holding onto a detached high-tech steering wheel.