U.S. Republican presidential hopefuls Mitt Romney and Newt Gingrich are battling for support in the southern state of Florida, which holds its primary in two days.

The two front-runners in the race to determine who will challenge President Barack Obama this year were campaigning around Florida Saturday.

Romney, a multimillionaire investor and former governor of Massachusetts, holds the lead in the latest polls.

The campaign of former U.S. House of Representatives Speaker Gingrich received the endorsement Saturday of a former rival for the nomination — pizza magnate Herman Cain. Cain dropped out of the race in early December after he was accused of sexual harassment and marital infidelity.

The other two candidates, former Pennsylvania Senator Rick Santorum and Texas Congressman Ron Paul, were trailing by a wide margin.

With the battle for the nomination evolving into a two-man race, Romney and Gingrich have traded criticisms and attack ads. Romney has blasted Gingrich for being found guilty of ethics violations that forced him to resign as House speaker, while Gingrich has slammed Romney for his wealth and business practices.

Romney needs a win in Florida to regain his momentum after losing to Gingrich in the South Carolina primary on January 21.

Romney won a decisive victory in the New Hampshire primary and was initially declared the winner of the first nominating contest in Iowa, before an updated vote tally revealed Santorum had won.