WASHINGTON A federal trade panel voted Friday to investigate whether Chinese companies are harming the U.S. solar panel industry by dumping low-price products on global markets.

U.S. companies' complaints about their Chinese rivals have been amplified by the controversy surrounding Solyndra Inc. - a California-based solar panel maker that went bankrupt after winning a half-billion-dollar federal loan from the Obama administration.

American companies have asked the government to impose steep tariffs on Chinese solar imports, and the unanimous vote by the International Trade Commission means the case will continue.

The solar panel manufacturers have been struggling against stiff competition from China as well as weakening demand in Europe and other key markets, just as President Barack Obama is working to promote renewable energy.

The failure of Solyndra embarrassed the administration and prompted a lengthy review by congressional Republicans who are critical of Obama's green-energy policies. Solyndra, which isn't involved in the ITC case, cited Chinese competition as a key reason for its failure.

The commission's vote does not impose any penalties but says there is reason to believe that Chinese imports harm or threaten to harm the U.S. solar panel industry. The companies that filed the complaint said the ruling affirmed their claims that massive subsidies by the Chinese government are enabling Chinese producers to drive out U.S. competition.

U.S. energy officials say China spent more than $30 billion last year to subsidize its solar industry. Obama said last month that China has "questionable competitive practices" on clean energy and that his administration has fought "these kinds of dumping activities." The administration will act to enforce trade laws where appropriate, Obama said.

SolarWorld Industries America Inc., the largest U.S. maker of silicon solar cells and panels and a subsidiary of Germany-based SolarWorld, is leading the U.S. complaint.

Ben Santarris, a spokesman for the Oregon-based company, called the decision to continue the case "a positive step toward restoring sustained international competition."

But the trade dispute has caused a split in the solar industry. Some U.S. companies argue that low-priced Chinese imports have helped consumers and promote rapid growth of the industry.

To counter the trade petition, a group of solar companies have formed the Coalition for Affordable Solar Energy. Members include California-based SunEdison, Recurrent Energy, Solar City and Westinghouse Solar, as well as China-based SunTech.

The companies argue that the U.S. complaint could spark a trade war with China and raise prices for the entire industry.