The U.S. Department of Commerce on Wednesday launched investigations into China-made seamless steel pipes that could lead to new tariffs and thus escalate the trade disputes between the two countries.

The department said it had initiated anti-dumping (AD) and countervailing duty (CVD) investigations at the request of the U.S. Steel Corporation, V&M Star LP, TMK IPSCO and the United Steelworkers (USW).

The U.S. petitioners requested a 98.37-percent anti-dumping duty against the Chinese imports and additional countervailing duties to offset what they allege are Chinese government subsidies.

The U.S. International Trade Commission (USITC) is scheduled to make its preliminary injury determination on or around Nov. 2 of this year.

The U.S. Department of Commerce is scheduled to make its CVD preliminary determination in December and its AD preliminary determination in February 2010, if the USITC decides against the Chinese imports.

Dumping occurs when a foreign company sells a product in the United States at less than normal market value.

Subsidies are financial assistance from foreign governments that benefit the production, manufacture or exportation of goods.

From 2006 to 2008, imports from China of seamless steel pipes increased 131.52 percent by volume, and were valued at an estimated total of 382 million U.S. dollars in 2008, according to U.S. government data.

U.S. President Barack Obama recently decided to impose tariffs for three years on all car and light truck tires imported from China.

The move has been denounced by China as a "serious act of trade protectionism."