China's Ministry of Commerce spokesman Yao Jian said Friday the U.S. decision to impose preliminary duties on Chinese potassium phosphate salts and coated paper was unfair and discriminatory.

Yao said "frequent" countervailing probes by the U.S. into Chinese products have "unfairly restricted normal exports," adding the fresh anti-dumping measures came only two years after the U.S. ruled China's coated paper exports did not harm the domestic industry in November 2007.

The two products will face 109 percent and up to 13 percent duties, respectively, according to a U.S. Commerce Department statement Tuesday.

Yao said the fundamental reason behind the difficulties in the U.S. coated paper industry was due to weak demand caused by the financial crisis. He said passing the problem on to Chinese manufacturers was unacceptable.

He said China firmly opposes abuse of trade protectionist measures by the U.S. and would negotiate with the U.S. over the unfair move to protect the interests of Chinese companies.