( Reuters )- White House hopefuls hammered home their closing messages on Saturday in a frenzied hunt for votes in Iowa, with Democrat Barack Obama promising a new type of politics and rival Hillary Clinton proclaiming her readiness to lead.
Republican Mitt Romney took more swipes at rival John McCain, Mike Huckabee criticized Romney's attack ads and Rudy Giuliani made a last visit to the Midwestern U.S. state five days before it opens the race to pick candidates in the November 2008 election to succeed President George W. Bush.
Polls show both the Democratic and Republican races remain close and unpredictable in Iowa, where a strong showing can give candidates valuable momentum going into other state contests starting with New Hampshire just five days later.
Clinton, Obama and John Edwards are in a tight three-way battle among Democrats, with some polls showing Edwards gaining ground.
Romney and Huckabee are fighting for the lead among Republicans, but up to one-fifth of the state's voters in both parties could still change their minds, according to polls.
In caravans of buses and vans, candidates rolled across Iowa's snowy roads and visited small towns in all corners of the state to plead for support.
Obama , a first-term Illinois senator who has faced charges of inexperience, stuck to his message that he was the candidate best suited to change Washington's way of conducting business.
"We can't settle for the same old politics anymore. We need a fundamentally new kind of politics," Obama told the crowd in Burlington, a mixture of young college students and gray-haired men gripping canes.
Obama's camp also kept up its criticism of the influx of big spending in Iowa by outside groups supporting Clinton and Edwards, particularly a group headed by a former Edwards aide.
Obama campaign manager David Plouffe said in a statement that Edwards "simply exploited the biggest loophole in the campaign finance system" to benefit from the arrangement while taking public matching funds.
Edwards has said he does not take money from lobbyists or special interests and did not coordinate with the group.
Clinton, a New York senator and former first lady, said in Eldridge, Iowa, there were two questions facing voters in the final days of the state's race.
"Who is ready to be president on day one, to take responsibility for the serious issues that our country faces, and who can run a winning campaign to make sure that the Democrats take back the White House?" she asked.
"I'm very comfortable with Iowans answering those questions and coming out to caucus for me," Clinton said.
Former President Bill Clinton, campaigning for his wife in New Hampshire, said she was best qualified to deal with any unexpected crisis.
"President Bush never talked about Osama bin Laden and didn't foresee Hurricane Katrina. If you're not ready for that, then everything else you want to do can be undermined," he said in Nashua. "I think on this score she's the best of all."
Romney, the former Massachusetts governor, has seen big leads in Iowa and New Hampshire disappear under the recent surges of Huckabee in Iowa and McCain in New Hampshire.
For the second consecutive day he unveiled a television ad criticizing McCain on his support for a failed Senate bill that would have given illegal immigrants a path to citizenship.
"McCain championed a bill to let every illegal immigrant stay in America permanently," the ad's narrator says, noting Romney's get-tough stance on illegal aliens.
McCain, an Arizona senator, said while campaigning in New Hampshire he thought the state's voters were sophisticated enough to see through the ads. He took another jab at Romney's shifting views on some topics.
"It's hard to respond sometimes because the position he has today may not be the position he has tomorrow," McCain said.
Huckabee , a former Arkansas governor and the target of a Romney ad on Friday, said while campaigning in Osceola that Romney was becoming "dishonest" in his attacks.
"He's dishonest toward me, he's dishonest toward John McCain and it's unfortunate that he's resorted to those kinds of attacks," said Huckabee , who has connected strongly with evangelical Christians and surged in recent polls.
Giuliani, the New York mayor during the September 11 attacks who has largely bypassed Iowa to focus on later voting states, made his final visit before Thursday's caucuses and said he would "do fine" in them.
Speaking to supporters at his suburban Des Moines campaign headquarters, he stressed his experience as mayor and mentioned the September 11 attacks five times during a 15-minute speech.
"I think of an America in which everybody can look up ... and we can dream," Giuliani said. "We can dream about success."