BOSTON (AP) — Republican presidential candidate Mitt Romney has decided to pull his advertising from South Carolina, where he was hoping to take on Mike Huckabee and John McCain, and from Florida, where Rudy Giuliani has been spending time and money.

"We feel the best strategy is to focus our paid messaging in Michigan," Romney spokesman Kevin Madden said Wednesday.

The decision comes on the heels of back-to-back second-place finishes in Iowa and New Hampshire for the former Massachusetts governor. Romney, a multimillionaire who had used some of his own cash, had invested heavily in both states, counting on the two to give him the momentum toward the nomination.

Earlier on Wednesday, Romney had assured his top financial backers that he will win the upcoming Michigan primary, as he and his staff worked to soothe supporters unsettled by his losses in the Iowa caucuses and New Hampshire primary.

"It's just getting started," the presidential contender told hundreds of supporters gathered at a convention center for a followup to the "National Call Day" that raised an unprecedented $6.5 million a year ago

He promised to carry on to Michigan, which votes Jan. 15, as well as Nevada and South Carolina, which vote Jan. 19.

The public spectacle, a rarity for the normally tightly controlled Romney political operation, included appeals for calm from a top financial backer, eBay CEO Meg Whitman, and a top political supporter, former Sen. Jim Talent of Missouri.

"To a person, we remain incredibly optimistic that we still have a chance to win this thing," Whitman told the crowd, which included everyone from Fortune 500 executives to entrepreneurs.

Spencer Zwick, Romney's national finance director, told the phone bankers: "If for some reason he is not the nominee, all those funds will be returned to the donor himself."