JACKSONVILLE, Fla. — Newt Gingrich and Mitt Romney intensified their bare-knuckles rhetorical brawl Thursday, with Gingrich verbally savaging the former Massachusetts governor, the campaign ads he’s run in Florida and even the Republican Party establishment.

As Gingrich blasted away, Romney coyly but clearly returned fire at the former speaker of the House of Representatives during a campaign event in Jacksonville, portraying Gingrich as the consummate Washington Beltway insider.

Speaking in friendly territory — before a tea party crowd of about 500 in Central Florida’s Mount Dora — Gingrich wasted little time before going after Romney and the barrage of TV ads that Romney’s campaign and pro-Romney super PACs have saturated Florida’s airwaves with before Tuesday’s Republican presidential primary in the state.

“This is the desperate last stand of the old order, throwing the kitchen sink, hoping something sticks, because if only they can drown us in enough mud — raised with money from companies and people who foreclosed on Floridians,” Gingrich said, adding that the PAC ads were “paid for with money taken (from) the people of Florida, by companies like Goldman Sachs.”

Gingrich, who surged in Florida polls immediately after his primary victory last Saturday in South Carolina, said the race was now “very close” but conceded that the “weight of the negative ads” and what he called Romney’s “dishonesty” had “hurt us some.”

Gingrich also had choice words for the GOP establishment, calling it “just as much an establishment as the Democratic establishment.” Several high-profile senior Republicans — such as former President George H.W. Bush, former New Hampshire Gov. John Sununu and former Senate Majority Leader Bob Dole of Kansas, have endorsed Romney.

“And they are just as determined to stop us,” Gingrich said. “Make no bones about it, this is a campaign for the very nature of the Republican Party and the very opportunity for a citizen conservatism to defeat the power of money and to prove that people matter more than money, than Wall Street, and people matter more than all the big companies that are pouring cash into Romney ads that are false.”

Gingrich’s jab at the GOP came as the Romney campaign released a letter from Dole that’s sharply critical of Gingrich, his leadership skills and his scruples.

“If Gingrich is the nominee it will have an adverse impact on Republican candidates running for county, state and federal offices,” Dole wrote. “Hardly anyone who served with Newt in Congress has endorsed him and that fact speaks for itself. He was a one-man-band who rarely took advice. It was his way or the highway.”

The letter mentions the House ethics investigation that led to Gingrich becoming the first speaker ever to be punished by the House — on a 395-28 vote in the Republican-controlled chamber — for ethics violations. He also had to pay a $300,000 fine.

“His mounting ethics problems caused him to resign in early 1999,” Dole wrote, adding of Gingrich’s time as speaker: “Gingrich had a new idea every minute and most of them were off the wall.”

Romney, at a morning campaign event in Jacksonville, didn’t mention Gingrich by name as he addressed a crowd of about 200 outside a printing plant that’s going out of business. Instead, he said Floridians had two distinctly different options to choose from on Tuesday.

“Florida is going to make a decision about who is going to be our nominee, and I’ve got to admit: I’ve never lived in Washington, D.C.,” Romney said. “I’m not part of the culture of Washington, D.C. I spent my life outside of Washington, D.C. I lived my life on Main Street and on other streets across this country. I want to use the experience I’ve had, working in the real economy, to go to Washington and fix it.”

He added: “Now if you think that you really need someone who has been part of the culture of Washington for the last 35 years to go there again and continue in Washington, why, there are other people you can choose.”

Gingrich has lived in the Washington area since he was first elected to the House in 1978.

Romney spent most of his time at his lone campaign appearance before Thursday night’s televised debate attacking President Barack Obama and his economic policies.

“This has been a ‘Groundhog Day’ presidency,” he said. “He keeps saying the same things and we keep waking up with the same things going on. … It’s been a ‘Groundhog Day’ presidency, and that’s going to end if I’m president.”

As Romney and Gingrich jousted, former Sen. Rick Santorum, R-Pa., sought to quell rumors that he’s on the verge of dropping out of the race.

Santorum will take time away Friday from campaigning in Florida to raise money in Pennsylvania and Virginia. He’ll be back in the Sunshine State on Saturday.

“We’re not going anywhere,” Santorum said in Tallahassee. “We’re staying in this race for the long haul. I think we’re playing for the next states.”

Still, questions persisted because Santorum isn’t looking toward any election night event Tuesday. He’ll be in Florida on Sunday and Monday for events, but is making no promises after that.

“We’re just trying to figure out Monday, from that point on what we’re going to do, and whether we’re going to stay here on Election Day, when you really can’t campaign. Maybe start going to another state and start doing some campaigning. We want to use every single day to campaign. And we’re sort of up in the air to exactly how that works.”