DUBUQUE, Iowa/MENTOR, Ohio - After months spent rallying their most reliable supporters, Republican Mitt Romney and US President Barack Obama reached out on Saturday to the small sliver of voters who remain undecided in the final days before Tuesday's presidential election.

With the race in a dead heat nationally, both candidates hopscotched across the country in a bid to secure any possible advantage ahead of Election Day. That meant another round of campaigning in the handful of states that remain competitive and a last-minute effort to pull votes from the other side.

US President Barack Obama speaks at a campaign event at Mentor High School in Ohio, Nov 3, 2012.[Photo/Agencies]

At airport rallies in New Hampshire and Iowa, Romney urged supporters to try to sway friends and neighbors who back Obama. He said he would reach out to Democrats as well if elected - a stance that could appeal to independent voters who have little stomach for partisan gridlock.

"I want you to reach across the street to the neighbor, who has that other sign in his front yard. And I'm going to reach across the aisle in Washington, D.C., to the politicians who are working for the other candidate," Romney told about 2,000 people at an airport rally in Dubuque, Iowa.

In Ohio, Obama hammered Romney for opposing his bailout of the auto industry and trying to scare workers.

"I understand that Governor Romney's having a hard time here in Ohio because he was against saving the auto industry," Obama said. About one in eight jobs in Ohio is tied to auto manufacturing. The bailout appears to have boosted Obama's prospects in the Rust Belt state, especially among the working-class white men who are heavily backing Romney in much of the rest of the country.

"I've been a Republican for 35 years and I've never voted for a Democrat on the federal level - until now," retiree Patrick Dorsey said as he waited for Obama to speak. "Economically, Romney's just going to make the rich richer."

Tight race in polls

Romney will have a hard time winning the White House if he does not carry Ohio, and a Reuters/Ipsos poll released on Saturday showed him trailing Obama by a statistically meaningless margin of 1 percentage point in the state. Other polls show him trailing by a larger margin in Ohio.

The race for the White House remains effectively tied at a national level with 47 percent backing Obama and 46 percent backing Romney, according to a Reuters/Ipsos daily tracking poll released on Saturday.

The narrow scope of the race has been evident for months but it was shown vividly on Saturday, when Obama was due to campaign in Dubuque six hours after Romney's visit.

Still, analysts say Obama holds an edge in many of the eight or nine competitive states that will determine who controls the White House. Reuters/Ipsos polls released on Saturday showed Obama leading by 3 percentage points in Virginia but trailing by 2 points in Colorado. The two were dead even in Florida. All the results were within the credibility interval, a measurement of the accuracy of online polls.

Other surveys generally show Obama leading by narrow margins in Wisconsin, Nevada, New Hampshire and Iowa. Romney is considered to have the edge in North Carolina.