The U.S. Commerce Department said Thursday that it would slap preliminary anti-dumping duties on imported magnesia carbon brick from China, the latest move that adds tension to the trade relations between the two countries.

In this case, the product, a certain fire-resistant construction material, will face duties of up to 349 percent.

The department said in a statement that it had "preliminarily determined" that Chinese producers and exporters sell the product in the United States at less than fair value.

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

Some Mexican exporters also face anti-dumping duties in the same case. But their preliminary dumping rate is 54.73 percent.

According to the U.S. government data, from 2006 to 2008, imports of certain carbon bricks from China increased 3.78 percent by volume and were valued at about 50.8 million dollars. Imports of the same product from Mexico increased 7.66 percent by volume and were valued at an estimated 7.7 million dollars in 2008.

The Commerce Department is scheduled to make its final decision in July.

The new case followed the Department's preliminary sanctions on imported Chinese potassium phosphate salts and coated paper on March 2.

Prior to that, the U.S. International Trade Commission (ITC), an independent federal agency, made final decision to impose punitive tariffs on imported Chinese steel pipes for alleged unfair subsidies, a move 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 amid the global financial crisis, economists warned.