Republican presidential candidate, former Massachusetts Gov. Mitt Romney, campaigns at the Fish House in Pensacola, Fla., Saturday, Jan. 28, 2012. (AP Photo/Charles Dharapak)

(CNSNews.com) - Former Mass. Gov. Mitt Romney on Monday called it "very sad and painfully revealing" to see "Newt Gingrich railing on" about Romney's supposedly liberal positions.

Gingrich on Sunday called Romney a "pro-abortion, pro-gun control, pro-tax-increase liberal" who could not be trusted to bring conservative values to the White House.

In an appearance on Fox & Friends Monday, Romney refuted Gingrich's comments: "I am pro-life; I support the Second Amendment -- I don't support any new laws to limit guns in some ways; and obviously, I'm not in favor of any tax increases -- I cut taxes 19 times as governor."

Romney said Gingrich is "working very hard to find a message that will distinguish himself from the rest of the field," and Romney then criticized Gingrich's experience as Speaker of the House, which was marred by an ethics investigation and opposition from some of his fellow Republicans.

"The campaign here in Florida  has been about leadership and the capacity to lead -- and whether an individual has a successful record as a leader or not; whether the people who worked with that person as a leader, whether they support him or not. And of course the ultimate issue is, who can bring real conservative change to Washington," Romney said.

Gingrich, who previously has branded Romney as a "Massachusetts moderate," is now calling Romney a "liberal" -- and Gingrich promises to take the nomination fight all the way to the Republican National Convention.

Romney leads in most Florida polls heading into Tuesday's primary election.