The Obama administration moved Thursday to impose stiff new tariffs on solar panels made in China, the latest in a series of trade disputes between the world's two biggest economies and sparking accusations by Beijing of protectionism. The Commerce Department said Chinese producers had dumped solar cells and panels in the United States at margins ranging from 31 percent to nearly 250 percent. If the preliminary ruling is upheld, tariffs averaging 31 percent could be imposed on Chinese solar-panel imports. The tariffs would be in addition to fees ranging from 2.9 percent to 4.73 percent imposed in March after the department found that China is improperly subsidizing its solar manufacturers. The tariffs announced Thursday were higher than expected and could ratchet up trade tensions between the two countries. Business Week [highlights] Several U.S. solar panel makers, led by Oregon-based SolarWorld, had asked the government to impose steep tariffs on Chinese imports. They are struggling against stiff competition from China as well as weakening demand in Europe and other key markets. Bloomberg China could retaliate against U.S. companies doing business there, and Chinese authorities have announced their own probe into whether U.S. support for renewable energy companies hurts foreign suppliers. Bloomberg The United States already has punitive duties on steel pipe, pencils, electric blankets and bedspring imports from China and was also reported in March to be investigating if imports of stainless steel sinks are sold at unfairly low prices. Reuters Chinese officials have threatened to impose trade duties on U.S. shipments of polysilicon, the key material used in solar panels, if the U.S. moves to penalize Chinese solar companies. WSJ "The anti-dumping ruling increases the risk of retaliatory action by Chinese government on U.S. polysilicon imports into China," Deutsche Bank said in a report. WSJ [/highlights] AHT/HJ