The Obama administration is putting pressure on China over its trade policies.
The U.S. indicated on Thursday it plans to get tougher when it comes to both trade and efforts to reform the Chinese currency system. The U.S. filed two new cases against the People's Republic before the World Trade Organization.
Critics say the Chinese yuan is undervalued compared to the dollar, and that makes Chinese products cheaper in the U.S. and American products more expensive in China.
"We are very concerned about the negative impact of these policies on our economic interests," U.S. Treasury Secretary Timothy Geithner said in testimony prepared for hearings of the Senate Banking Committee and the House Ways and Means Committee.
The Chinese government controls the value of its currency and has been allowing it to rise in value against the dollar.
However, Geithner said it's not enough, arguing that the China has been moving too slowly to fix the problems.
"We are concerned, as are many of China's trading partners, that the pace of appreciation has been too slow and the extent of appreciation too limited," he said
Chinese Foreign Ministry spokeswoman Jiang Yu rejected such criticism, saying appreciation of the yuan "can't solve the trade deficit with China."
"Pressure cannot solve the issue," she added. "Rather, it may lead to the contrary."