The US Commerce Department said on Thursday that it has set preliminary antidumping duties (AD) on imports of certain seamless refined copper pipe and tube from both China and Mexico.

The department said in a statement that it "preliminary determined that Chinese and Mexican producers/exporters have sold copper pipe and tube in the United States at margins ranging from 10.26 to 60.50 percent, and 29.52 to 32.27 percent, respectively."

Some nine Chinese exporters, qualified for a separate dumping rate from 10.26 to 34.48 percent, while all other Chinese exporters received a preliminary dumping rate of 60.50 percent, said the US agency.

As a result of this preliminary determination, Commerce will instruct US Customs and Border Protection to collect a cash deposit or bond based on these preliminary rates. In 2009, imports of copper pipe and tube from Mexico and China were valued at an estimated 130.3 million US dollars and 233.0 million dollars, respectively, according to the Commerce Department.

The department said that it is currently scheduled to make its final determination in September 2010.

If Commerce makes an affirmative final determination, and the US International Trade Commission makes an affirmative final determination that imports of copper pipe and tube from China and Mexico materially injures, or threaten material injury to, the domestic industry, Commerce will issue an antidumping duty order.

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

The onset of the global recession appears to have set off an increase in trade disputes around the world.

Globally, new requests for protection from imports in the first half of 2009 are up 18.5 percent over the first half of 2008, according to the World Bank-sponsored Global Anti-dumping Database organized by Chad P. Bown, a Brandeis University economics professor.

That increase follows a 44 percent increase in new investigations in 2008. And China has become the main target of the rising protectionism.