Republican presidential challenger Mitt Romney has addressed his secretly taped disparaging remarks about the 47 per cent of Americans he said don't pay federal income taxes, calling his words "just completely wrong."

Romney set the record straight hours before a closely watched U.S. jobs report gave President Barack Obama an upbeat end to a startling week for both campaigns.

The government's new jobs report Friday showed the U.S. unemployment rate fell to 7.8 per cent last month, dropping below 8 per cent for the first time in nearly four years. Unemployment had been at 8.1 per cent, and economists had expected the number to edge up instead.

The report broke an important psychological barrier before the Nov. 6 election. No president has been re-elected with unemployment above 8 per cent since the Great Depression.

The report has the potential to swing momentum back to Obama after he suffered through a weak first debate against Romney on Wednesday night.

The final monthly jobs report before the election will come just days before Nov. 6.

Romney's campaign had been hit hard by the secretly taped remarks that emerged last month, in which he said he couldn't convince nearly half the country to "take personal responsibility" for their lives. He slipped behind Obama in some of the key battleground states that will decide the election as people again worried that the multimillionaire Romney was out of touch with average Americans.

But Romney's assertive debate performance against a tired-seeming Obama rallied Republicans again to his side.

Obama notably did not mention Romney's "47 per cent" comment during the debate, but Romney brought it up in a Fox News interview Thursday night, after a day of rallying conservative activists with his vision of his own inauguration.

He told Fox that the remarks, which he had once dismissed as "not elegantly stated," were wrong.

'Well, clearly in a campaign, with hundreds if not thousands of speeches and question-and-answer sessions, now and then you're going to say something that doesn't come out right.' —Mitt Romney

"Well, clearly in a campaign, with hundreds if not thousands of speeches and question-and-answer sessions, now and then you're going to say something that doesn't come out right," Romney said. "In this case, I said something that's just completely wrong."

He added: "And I absolutely believe, however, that my life has shown that I care about 100 per cent and that's been demonstrated throughout my life. And this whole campaign is about the 100 per cent."

Widespread anger over Romney's remarks had helped to give Obama a bit of a lift in key polls, and many wondered why the president didn't use them to fight back in Wednesday's debate, which most people agreed the newly energized Romney won.

Obama's campaign on Thursday promised "adjustments" would be made before the two debates that remain. And Obama woke up during campaign appearances Thursday to make a rebuttal, accusing Romney of being dishonest about how his policies would affect the tax bills of middle-class families.

Both campaigns faced a potential turning point with the release of Friday's jobs report.

Romney has been trying to cast Obama as ineffective in job creation.

Last month's weak hiring numbers came out just a day after Obama delivered his acceptance speech at the Democratic National Convention. They didn't appear to interfere with Obama's post-convention bounce in public opinion polls or with perceptions that he would be as good as Romney at creating jobs.

The U.S. unemployment rate had been fluctuating between 8.1 per cent and 8.3 per cent since January after being stuck at between 8.9 per cent and 9.1 per cent for 10 months in 2011.

Obama advisers have maintained that the rate is less important than the trajectory.

"I think that there's a broad recognition of where we are," Obama campaign senior political adviser David Axelrod said before Friday's report came out. "So unless they're startlingly different, I don't think that this particular jobs report is going to be determinative. That's been the pattern. People understand we're in a long-term project here and we have to keep moving forward."

A recent Associated Press-GfK poll found that the vast majority of voters already have settled on a candidate, but 17 per cent of likely voters are considered persuadable — either because they are undecided or show soft support for Obama or Romney.

Their next debate is Oct. 16.

Obama and Romney both planned events in Virginia on Friday, reflecting the hotly contested race for the state's 13 electoral votes. The election is decided in state-by-state contests and not by nationwide popular vote.