LAKELAND, Fla. -- Mitt Romney and Paul Ryan called for "accountability," both for President Barack Obama and themselves, on the heels of accepting the GOP presidential nomination.

The newly-minted Republican presidential and vice presidential nominee held a sendoff rally here near Tampa, Romney's first public appearance since last night's address to the Republican National Convention.

“We want to be held accountable for the promises we made last night, and the night before. Paul Ryan and I both spoke to the American people about what we’ll do if we become president and vice president," Romney said, urging Americans to also measure Obama by the promises he has either kept or discarded.

Ryan, who accepted the vice presidential nomination on Wednesday, told the crowd of roughly 2,000 supporters that he felt he and Romney had emerged from Tampa offering a "our fellow countrymen a very clear choice" in visions of leadership for the next four years.

Romney said he was "embarrassed" by the tributes and stories about his life told last night by members of his church, his family, and by those touched by his tenure at the Olympics in Salt Lake City or at the statehouse in Massachusetts. He said some of the stories were "overly generous," but he appreciated them nonetheless.

Romney and Ryan will now part ways -- on newly unveiled official campaign planes -- for separate campaign stops to round out the week. Romney will head to South Louisiana to tour storm-damaged areas with Louisiana Gov. Bobby Jindal, and Ryan will stump in Virginia at a campaign stop originally envisioned as a joint appearance for the ticket.