U.S. Trade Representative Ron Kirk said at a news conference that the U.S. is "deeply troubled at what appears to be a conscious policy to create unfair advantages for Chinese industries."

The European Union also filed its own case on the matter, setting the stage for what could be a key showdown among the world's major trading countries.

As stated in the US complaint documents, the  raw materials at issue include coke, bauxite, magnesium and silicon metal. The U.S. and EU complaints say China's export restrictions give its companies an unfair edge over their foreign rivals by giving them access to cheaper materials, despite WTO rules against export controls.

The U.S. complaint  specifies  that China has in place  a number of measures that  restrict the export of raw materials for products for which it is either the world's largest producer or one of the top, such as coke, a key ingredient in steel production.

The U.S. document  cited as "a prime example of the highly distortive effects of China's export restraints" was its decision to limit exports of coke from 336 million metric tons in 2008, down to current annual exports of only 12 million metric tons.

Meanwhile, China "deeply regrets" the U.S. International Trade Commission's (ITC) ruling the previous day that U.S. manufacturers are being materially injured by imports of Chinese-made tires for certain passenger vehicles and light truck tires. A  Chinese Commerce Ministry spokesperson said in a statement that the ITC decision violates rules set under the World Trade Organization.

ITC said Thursday it found certain passenger vehicles and light truck tires from China are being imported to the United States in such increased quantities or under such conditions as to cause or threaten to cause market disruption to the domestic producers of like or competitive products.

Yao Jian, the spokesman for the Ministry of Commerce (MOC) said lots of evidence have proved that the Chinese-made tires did not cause direct competition with the US products. Restriction of the Chinese imports can not fix the structural problem in the US, he said.

As a result of the affirmative determination, the ITC will consider the  corrective measures and  send its report to the US President and the US Trade Representative by July 9.