The U.S. Commerce Department said on March 2 that it would impose preliminary countervailing duties on potassium phosphate salts and coated paper imported from China, a move that may escalate tensions between the two countries. The two products will be levied 109 percent and up to 13 percent duties, respectively. The final decision will be made in July.

Potassium salts are used in industrial cleaning products, fertilizers and food additives, while coated paper is used in printing corporate annual reports and high-end catalogues and magazines.

The new case followed a recent decision by the U.S. International Trade Commission to impose punitive tariffs on imported Chinese steel pipes for unfair subsidies. The Chinese Government denounced the move as "protectionist".

Economists warned the protectionist moves by the Obama administration will ultimately hurt China-U.S. trade relations, which are playing an important role in global trade after the 2008 economic turmoil.