WASHINGTON » Competing for white working-class voters, President Barack Obama and Republican Mitt Romney squared off today on China and accused each other of backing policies that would move American jobs overseas as the U.S. economy struggles to recover.

“In 2008, candidate Obama promised to take China ‘to the mat’,” Romney said in his weekly podcast. “But since then, he’s let China run all over us.”

Obama’s team, in turn, argued that Romney has profited from and outsourced jobs to China. The president also rolled out a new 60-second, $6 million ad campaign that casts Romney as risky for the nation’s recovery and features former President Bill Clinton saying: “They want to go back to the same old policies that got us in trouble in the first place.”

Seven weeks before Election Day, both candidates took a rare break from campaigning even as they intensified their efforts on the economy, through the prism of China, with Obama sensing an opportunity to undercut his Republican rival’s strength and Romney refusing to cede ground. The maneuvering came as a new poll showed Romney having lost his long-held advantage on the economy to the president even as the overall contest remains tight.

For Romney, emphasizing China was a way to refocus his campaign on voters’ No. 1 issue and the central one of his campaign after a difficult week dominated by foreign policy, a weak spot for the Republican, in the wake of unrest at U.S. embassies in the Middle East. The shift to China also indicated Romney’s need to shore up support among the working-class voters he needs to turn out in big numbers come November.

Obama’s campaign said it welcomed the fight on China, an issue where it argues Romney has numerous vulnerabilities. It released a new web video Saturday in which Obama deputy campaign manager Stephanie Cutter said Romney holds investments in Chinese companies and outsourced jobs to China while running the private equity firm Bain Capital.

Obama’s quick counter underscored the importance of holding onto his recent gains in Ohio, a swing state with a large manufacturing base where many blame China for depressing the state’s industry.

The tit-for-tat on China started percolating late last week.

Romney released a television advertisement Thursday accusing Obama of “failing American workers” and ignoring unfair trade practices by China. Obama followed up a day later with a TV spot focused on its claims that Romney outsourced jobs to China while working in the private sector.

Those commercials are dominating the campaign conversation in key states where the race will be decided even as the national campaign conversation focuses on foreign policy in the aftermath of unrest at U.S. embassies that left an American ambassador and three others dead.

China — and through it the economy — has become Romney’s core argument as he woos voters in battleground states; it’s the only spot Romney’s campaign was running over the weekend in the eight states likely to decide the election: Ohio, Florida, Virginia, Iowa, New Hampshire, Colorado, Nevada and North Carolina. The campaign no longer is running the 15 state-specific ads it rolled out in a $4.5 million ad blitz the day after the Democratic convention, according to officials who track campaign advertising.

Both candidates left it to their advisers to haggle over China on Saturday.

Romney conferred with advisers at the Belmont, Mass., home of his son Tagg, then watched his grandson’s soccer game. The president spent the day at the White House and had no public events.

But his campaign got a jump on the day with an early morning launch of the new ad that claims Romney’s economic plan caters to multimillionaires over the middle class.

“We’re not going back, we are moving forward,” Obama says in the commercial that’s set to air in the seven most competitive states; Colorado, Florida, Iowa, New Hampshire, Nevada, Ohio, and Virginia.

Romney campaign spokesman Ryan Williams called the ad “false and misleading.”

Obama’s new ad is an expensive and expansive effort to gain an upper hand on the economy at a time when voters are reporting feeling slightly more optimistic that the president’s policies are helping. A new national survey by The New York Times and CBS News finds that Romney has lost his long-standing edge on the question of who voters view as most likely to restore the economy and create jobs. Despite that, the poll found the race narrowly divided.

Polls in several of the most contested states also show the president with a slight edge.

Democrats say Obama has gained an advantage on the economy in part because Romney hasn’t laid out specific plans for what he would do differently. And they see signs that voters, even those who say their economic situation isn’t better today, believe it will be in a year or two, making it more likely they’ll want to stick with Obama.

Romney’s campaign advisers say Obama hasn’t done anything to change the dynamic on the economy and claim any Obama gains are in states that would back the president in the fall anyway.

Republican outside groups acknowledge Obama has gotten a burst of support across the board, including on the economy, since his convention wrapped up just over a week ago. But they insist the race is still within reach or statistically tied in key states and nationally.

The economy remains weak, and there’s no telling who voters will trust more to handle it come November.

Unemployment dropped to 8.1 percent last month, but only because more people stopped looking for work. Acknowledging the tenuous situation, the Federal Reserve announced this week that it would spend $40 billion a month to buy mortgage bonds for as long as it deems necessary to make home buying more affordable. It also plans to keep short-term interest rates at record lows through mid-2015 in an effort to jump-start the listless American economy.

On Saturday, Romney’s running mate, Wisconsin Rep. Paul Ryan, called the Fed’s action “sugar high economics” that would help banks and Wall Street, but not average Americans.

“We don’t need synthetic money creation,” Ryan said during a campaign stop in Oldsmar, Fla. “We need economic growth.”

Noticeably absent from that list of states where Obama’s new 60-second ad was running: North Carolina. Obama narrowly won the state in 2008, moving it into the Democratic column for the first time in nearly 40 years. But Democrats say he faces an uphill battle there in November given the state’s dour economy and its shift back to the right in statewide elections.

Obama’s campaign said cutting North Carolina out of its latest ad buy was not an indication that it was giving up on the state. The campaign is expected to spend just under $1 million in new ads in North Carolina next week.

Associated Press writers Kasie Hunt in Washington, Steve Peoples in Boston and Ken Thomas in Belmont, Mass., contributed to this report.