Mitt Romney is making a fresh bid for Ohio voters, trying to use post-debate momentum to make up ground in a state that has been a mainstay of Republican presidential candidates and could help President Barack Obama hold onto the White House.

Romney planned events in communities north of Columbus and Dayton on Wednesday, intensifying his efforts in the state after a strong debate performance that has helped him close a deficit against Obama in national polls.

"This economy is not creating the jobs it should. We've got to fix it," Romney said Tuesday in Cuyahoga Falls, Ohio, where he campaigned with New Jersey Gov. Chris Christie. "We're going to do it here in Ohio."

Ohio remained a focus for both campaigns, as Obama and Romney pushed for support on the last day of voter registration before Election Day. Obama returned to the White House following a fundraising trip through California and a stop Tuesday at Ohio State University, where he urged students to cast their ballots early.

"Don't wait. Do not be late. Go vote today," Obama said. "All right, Buckeyes, we need you." His campaign staged buses nearby, ready to ferry students or other supporters to registration centers. Obama was staying off the campaign trail on Wednesday and then heading to Florida on Thursday for events in the nation's largest battleground state.

Romney was campaigning in Ohio as his comments on abortion to an Iowa newspaper brought attention to social issues. Romney told The Des Moines Register in an interview Tuesday that he would not pursue any abortion-related legislation if elected president. His campaign tried to walk back the remarks, saying he would support legislation aimed at providing greater protections for life, without elaborating.

Republican presidential nominee Mitt Romney speaks during a campaign rally in Cuyahoga Falls, Ohio. (Shannon Stapleton/Reuters)

Obama's campaign jumped on the apparent shift, saying in a statement that "within just a couple hours of the story with Romney's abortion comments posting, his spokesperson clarified that he would in fact support legislation to restrict a woman's right to choose."

Obama's lead in Ohio narrowing

The attention on Ohio came amid signs that Obama's advantage in Ohio was narrowing. A new CNN poll showed Obama leading Romney 51 per cent to 47 per cent among likely Ohio voters, depicting a tighter race. Republicans said Romney's strong debate appearance has helped his standing in national polls and they were beginning to see evidence of that in the battleground states most likely to decide the election.

"There isn't any question that he has breathed new life and new energy into the Republican Party," Ohio Gov. John Kasich said Tuesday on a conference call with reporters. "We're seeing that there is greater intensity among Republicans and a great willingness to get out and vote and participate than we're seeing with Democrats."

With 18 electoral votes, Ohio remains a linchpin in Romney's strategy to string together enough state victories to amass the 270 Electoral College votes needed to take the White House. No Republican has won the presidency without this Midwestern state, and if Romney were to lose here, he would have to carry every other battleground state except tiny New Hampshire.

Romney has far fewer state-by-state paths to the White House than Obama, who still has several routes to victory should he lose in Ohio.

With less than a month before the election, Romney has increased his focus on the state: He's spending three of the next four days in Ohio before the second presidential debate in Hempstead, N.Y., on Tuesday. Running mate Paul Ryan meets Vice President Joe Biden on Thursday in Kentucky for the only vice presidential debate of the campaign.

Obama campaign spokeswoman Jen Psaki dismissed the impact of polls showing a tighter race, saying Democrats always expected the race in Ohio and elsewhere to narrow ahead of Election Day.

"We have blinders on. We're implementing our own game plan," Psaki said. "We're focused on getting our supporters out, communicating the choice."

Separately, Romney's campaign is trying to reach out to voters in new ways, dispatching Ann Romney to guest-host Good Morning America on Wednesday. Mrs. Romney was scheduled to be on hand for the morning news program's 8 a.m. hour, filling in for co-anchor Robin Roberts, who is on extended medical leave.