The United States on Tuesday dealt a blow to US manufacturers of solar panels and boosted shares in their Chinese rivals when it imposed preliminary punitive duties of less than 5 percent on imports from China. Nonetheless, the case adds to trade tensions between the world\'s two largest economies and threatens cooperation in the burgeoning clean-energy sector, which both countries say they want to promote. President Barack Obama, running for re-election in November, has promised to crack down on unfair Chinese trade practices and last week challenged China\'s export restrictions on critical \"rare earth\" industrial materials in a case filed with the European Union and Japan the World Trade Organization. Energy analysts had expected Chinese imports of solar panels to be hit with preliminary duties of 20 percent to 30 percent, but the rates announced on Tuesday ranged from just 2.90 percent to 4.73 percent. Shares in the leading Chinese solar companies erased early losses to rally on the New York Stock Exchange on the news, with Suntech Power Holdings closing 14 percent higher, Yingli Green Energy gaining 12 percent and Trina Solar climbing 8 percent. The Coalition for American Solar Manufacturing, a U.S. industry group that has complained that massive Chinese subsidies were driving them out of business, tried to put the best face on the news. It said it believed the U.S. Commerce Department would uncover more subsidies and unfair pricing practices as it continues its probe in the coming months, which would result in higher final duties. \"Today\'s announcement affirms what U.S. manufacturers have long known: Chinese manufacturers have received unfair and WTO-illegal subsidies,\" said Steve Ostrenga, chief executive officer of Helios Solar Works in Milwaukee, Wisconsin. Senator Ron Wyden, an Oregon Democrat who has been a driving force behind the case, also said he expected duties to \"significantly swell\" as the case proceeds. An attorney representing SolarWorld Industries America and other U.S. manufacturers said Commerce Department officials have only just begun to investigate some of the group\'s subsidy charges, providing hope duties would increase. China accounts for 114 of the 283 anti-dumping and countervailing duty orders the United States has on foreign goods. The Obama administration has imposed more than 50 anti-dumping and countervailing duty orders since taking office in January 2009, including about 40 against Chinese goods. The United States imported $2.8 billion worth of solar cells and panels from China in 2011, up sharply from about $1.2 billion just a year earlier, according to industry estimates. The Commerce Department will announce preliminary anti-dumping duties in May to address a separate set of charges that Chinese producers are selling solar panels in the US market at unfairly low prices. Chinese producers and US companies opposed to the duties said the preliminary decision on Tuesday belied charges that China was flooding its solar sector with subsidies. \"We\'re pleased and in large part feel vindicated,\" Robert Petrina, managing director of Yingli Green Energy\'s U.S. business said. \"I think it is a positive outcome and I think it really speaks to the crux of the argument.\" Jigar Shah, president of a coalition of U.S. solar panel sales and installation companies which were opposed to duties, called the ruling an \"initial victory for America\'s solar industry and its 100,000 employees\" because it would not significantly raise prices for solar products and hurt demand. Rob Stone, a solar analyst with financial services firm Cowen & Co, said the duties, however small, push solar panel prices in the wrong direction if the sector wants to become a viable alternative to fossil fuels. \"In the end, solar needs prices to go down more from where they are now, even though they\'ve come down precipitously,\" Stone said. \"This is why this whole thing is so stupid, because it will not help the small, uncompetitive U.S.-based manufacturers.\" SolarWorld Industries America, the US arm of leading German solar manufacturer SolarWorld AG, has led the U.S. industry coalition seeking import relief. The Commerce Department set a preliminary duty of 2.90 percent on SunTech Power Holdings, the world\'s biggest producer of photovoltaic solar panels, and a preliminary duty of 4.73 percent on Trina Solar, another major Chinese producer, industry officials said. All other Chinese solar panel producers and exporters received a duty rate of 3.59 percent. Importers will have to post bonds or cash deposits based on the preliminary countervailing duty rates while the department continues its investigation. The \"surprisingly low\" numbers would likely mean that the major Chinese companies would need to pay between about $5 million to $10 million to cover products shipped, said Timothy Arcuri, an analyst with Citigroup. While the dumping duty decision in May could impose a greater penalty on the Chinese companies, \"this by itself has relatively minimal impact,\" Arcuri said.