China said it was deeply concerned about a preliminary ruling by a U.S. trade body that trade practices by Chinese solar makers are hurting U.S. producers and said the decision underscored a U.S. inclination to trade protectionism.

Such protectionism measures would hurt bilateral trade and jeopardize mutual cooperation on new energy issues, China's Commerce Ministry said in a statement on its Web site.

The statement came after the U.S. International Trade Commission approved on Friday an investigation into charges of unfair Chinese trade practices in the solar-energy industry, setting the stage for possible steep U.S. duties and ratcheting up tensions with Beijing on the green-trade front.

The U.S. commission voted 6-0 that there was a reasonable indication that SolarWorld Industries America Inc. and other U.S. producers had been harmed by the imports or could have been.

The ruling was made without sufficient evidence showing [the] U.S. solar-panel industry has been harmed and ignored defenses from Chinese firms as well as opposition from the U.S. domestic industries and other stakeholders, the ministry said.

China is deeply concerned with the decision, which does not tally with facts and highlights the United States' strong tendency for trade protectionism.

China also hit back by saying that the United States should objectively analyze why some of its solar-panel firms lack competitiveness.

The vote allows the U.S. Commerce Department to continue an investigation that could lead to both countervailing and anti-dumping duties on solar cells and panels from China.

The dispute is one of several to have broken out on the environmental front, as governments seek to reduce dependence on carbon-emitting fossil fuels blamed for global climate change.

Chinese solar manufacturers most affected by the petition include Suntech Power Holdings Co. Ltd., Trina Solar Ltd., and Yingli Green Energy Holding Co. Ltd.

U.S. imports of the solar products from China totaled $1.5 billion in 2010, compared with $640 million in 2009.

(Reporting by Fayen Wong and Samuel Shen; Editing by Nick Macfie)