Mitt Romney on Friday wouldn’t commit to Florida’s first presidential primary debate, further upending a campaign that has swung from perfunctory to unsettled in a span of 48 hours.

Romney spokesman Ryan Williams said the campaign had “no announcements” on the Monday night debate, which is being hosted by the Tampa Bay Times, NBC News, National Journal and the Florida Council of 100.

Romney likely will decide whether to participate and under what terms after Saturday’s primary in South Carolina. Polls there show he now trails Newt Gingrich.

Gingrich pounced on the indecisiveness while campaigning in Orangeburg, S.C., saying that if Romney didn’t show, it would “become a running joke.”

“Romney can’t claim that he’s prepared to debate Obama if he’s not prepared to debate Newt Gingrich,” the former House speaker said. “So I’m confident he’ll be there Monday night.”

NBC officials said planning for the 9 p.m. debate set on the Tampa campus of the University of South Florida was continuing.

“We fully intend to proceed with this long-planned event, and we hope and expect all the qualifying candidates will participate,” NBC spokeswoman Erika Masonhall said.

NBC Nightly News anchor Brian Williams will moderate, with a panel including Times political editor Adam C. Smith.

This week, Romney strategist Stuart Stevens told the Washington Examiner that the campaign was becoming wary of debates. The Tampa debate would be the 18th major debate of the primary season, though just the second among the four remaining candidates — Romney, Gingrich, Texas Rep. Ron Paul and former Pennsylvania Sen. Rick Santorum.

“There are too many of these,” Stevens was quoted as saying. “We have to bring some order to it. We haven’t accepted Florida. … It’s kind of like a cruise that’s gone on too long.”

A Real Clear Politics average of polls show Romney comfortably ahead in Florida, with more than 40 percent of GOP supporters, followed by Gingrich with 22 percent, Santorum with 15 percent and Paul with 9 percent. The primary is scheduled for Jan. 31.

Florida is a crucial state for any Republican hoping to win the White House, but it’s also a critical primary state for Romney — who could possibly sew up the GOP nomination regardless of the outcome in South Carolina. The calculation could come down to whether Romney advisers think he could skip the debate — and take the heat that goes with that decision — and still carry the state.

“We look forward to campaigning across Florida and discussing Gov. Romney’s plans to create jobs and fix our economy,” Williams, his spokesman, said in an email.

A second Florida debate is scheduled for Thursday in Jacksonville, sponsored by CNN, the Republican Party of Florida and the Hispanic Leadership Network. RPOF spokesman Brian Hughes said he expects all candidates to participate.

Miami Herald staff writer Marc Caputo contributed to this report.