The U.S. Commerce Department said Tuesday that it would impose preliminary duties on imported Chinese potassium phosphate salts and coated paper, a move that may escalate trade disputes between the two countries.

In these countervailing duty (CVD) cases, the two products will face 109 percent and up to 13 percent duties, respectively.

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

The department said in separate statements that it had "preliminarily determined" that Chinese producers and exporters of the two products had received subsidies equivalent to the duties that were imposed.

"As a result of this preliminary determination, Commerce will instruct U.S. Customs and Border Protection to collect a cash deposit or bond based on these preliminary rates," said the statement.

According to the U.S. government data, from 2006 to 2008, imports of certain potassium phosphate salts from China increased 228 percent by volume and were valued at about 16.4 million dollars.

The Commerce Department will make its final determination in May.

The department said that it would also impose 17.48 percent preliminary duties on certain coated paper imported from Indonesia over the same issue of government subsidies.

In 2008, imports of certain coated paper from China and Indonesia were valued at an estimated 228.7 million dollars and 44.3 million dollars, respectively.

The final determination for the coated paper cases will be made in July.

The new case followed a recent final decision by the U.S. International Trade Commission (ITC), an independent federal agency, to impose punitive tariffs on imported Chinese steel pipes targeted for unfair subsidies. The move was denounced by the Chinese government as protectionism.

The protectionist moves by the Obama administration will ultimately hurt the U.S.-China trade relations, which are becoming more and more important due to the global financial crisis, economists warned.