Huckabee's news conference was set to unveil the new ad he shot this week, a 30-second commercial taking on Romney's record as Massachusetts governor. Huckabee instead said he pulled down the advertising purchase and would only talk about his campaign, not his competition's.

However, Huckabee still showed the anti-Romney advertisement at the news conference while the cameras were rolling, prompting Romney to respond.

"The press conference that Gov. Huckabee had today is confusing to the people of Iowa," Romney told reporters at a quick stop in Independence, Iowa. "On the one hand, he says he wants to run a positive campaign, on the other hand, he runs a negative campaign ad and hopes the people will promote it through the [news] media. That's a very confusing and puzzling message."

Huckabee and Romney are battling it out in a close race to win Thursday's Iowa caucuses, the first test of the GOP nomination process.

Romney has aired several advertisements and circulated mailers attacking Huckabee's record as Arkansas governor. Huckabee responded by blasting Romney as dishonest and misleading.

In an interview with CNN, Huckabee said he spent a lot of money on his advertisement - which was set to air starting at noon Monday - but that he changed his mind because he didn't want to run a negative campaign.

"If it costs me the caucus, it does," Huckabee said. "But I don't want to have to run an ad that I feel like I'm going to have to go take a shower after I run it."

Romney, too, toned down his advertising broadsides on Monday, airing a new spot that doesn't take on any of his rivals, but focuses on his own experience.

"I've spent my life tackling big problems - helping turn around business, the Olympics and state government," Romney says. "Together we can grow our economy, stop illegal immigration, defend life and preserve the values that make America the hope of the earth."

With less than three days until voters attend caucuses to choose their nominee, the campaigns stepped up their efforts.

Romney, who hit a pizza shop, a bed and breakfast and a hotel, and in the afternoon, was scheduled for two more events before attending a private family party.

Huckabee, meanwhile, opted for photo opportunities on Monday, first at a workplace in downtown Des Moines, then his news conference and finally, a haircut.

tburr@sltrib.com