NEW YORK - For the second time in as many weeks, Mitt Romney's campaign released a new television ad blasting President Barack Obama as weak against China on trade.

"Fewer Americans are working today than when President Obama took office," the ad's narrator says. "It doesn't have to be this way. If Obama would stand up to China."

The spot criticizes the Obama administration for not labeling China a "currency manipulator," a designation that would allow the United States to more directly confront China over actions that have cheapened Chinese exports, undercut the prices of American goods and produced economic growth rates for China several times that of the U.S.

While critics caution that such a label could ultimately trigger a trade war with China, Romney made the issue a main point of contrast earlier this month on the campaign trail.

"The president has had the chance year after year ... to label China a currency manipulator, but he hasn't done so and I will label China the currency manipulator they are on the first day," Romney told a crowd of supporters in Virginia.

The new 30-second ad, "Stand up to China," points to intellectual property violations that originated in China and took advantage of American goods, including computers and fighter jet technology.

"Obama had years to stand up to China," the narrator says. "We can't afford four more."

In fact, the Obama administration last week filed a complaint with the World Trade Organization alleging China has illegally subsidized automotive exports and undercut American suppliers. The president trumpeted the move while campaigning in the major auto territory of Ohio.

"It's not right. It's against the rules, and we will not let it stand," Obama said of the China trade policy. "American workers build better products than anyone. 'Made in America' means something. And when the playing field is level, America will always win."

But Romney's team hit back, saying in a statement the move was "too little, too late."

The new Romney ad Monday hits airwaves the same day the Republican presidential nominee launches a three-day bus tour in the Buckeye State.

The Romney campaign did not say where exactly the television ad would run or how much it spent on the ad buy.