BY JULIE PACE and NEDRA PICKLER

Associated Press

CINCINNATI

--Appealing to Rust Belt voters, President Barack Obama announced a new trade enforcement action against China on Monday, while Republican challenger Mitt Romney planned a greater emphasis on policy details that distinguish him from Obama to stop the incumbent's election momentum.

Romney's shift comes as Republicans openly fret about the state of their nominee's campaign and press him to give voters a clearer sense of how he would govern.

In newly published polls, Romney has lost the edge he held over Obama as the candidate better able to handle the federal budget deficit and taxes.

Romney pollster Neil Newhouse attributed Obama's gains to the bump the president received overall after the Democratic National Convention in North Carolina this month. But on taxes, Newhouse acknowledged Romney's need to do more to distinguish his plans.

"I'm not sure that voters really understand the differences between the plans Mitt Romney has and Obama has," Newhouse said. "And I think that's one thing we're committed to trying to do in moving forward is defining the differences between the two candidates on taxes."

One recent line of criticism from Romney appears to have brought a quick response from Obama.

The White House announced a move to stop Chinese subsidies of its auto industry--four days after Romney launched an advertising campaign accusing the president of allowing American manufacturing jobs to be lost to the Asian power.

The issue hits home among working class voters in manufacturing swing states such as Ohio, where Obama has gained recently in polls and touted his new action Monday.

The White House says more than 850,000 jobs in the state are related to the auto industry.

Obama told thousands gathered at a pavilion in Cincinnati's leafy Eden Park that Romney made money from companies that outsourced jobs to China while running the private equity firm Bain Capital.

The crowd jeered.

Obama responded, "Don't boo. Vote!"

"You can't stand up to China when all you've done is send them our jobs," Obama said. "You can talk a good game. But I like to walk the walk, not just talk the talk. And my experience has been waking up every single day doing everything I can to make sure that American workers get a fair shot in the global economy."