WASHINGTON -- A federal trade panel has found that imports of Chinese solar panels harm the U.S. solar industry.

Wednesday's unanimous vote by the U.S. International Trade Commission means steep tariffs imposed on China by the Obama administration in October will stand. It's the last step in a sweeping trade case that's gone on for more than a year.

A group of U.S. manufacturers complained that China's government is subsidizing companies that are flooding the U.S. market with low-cost products. The Commerce Department agreed, and imposed tariffs last month of up to nearly 250 per cent on Chinese companies.

The case has aggravated already tense trade relations with China. It's also caused a rift in the U.S. between manufacturers and solar panel installers, who stand to gain from low-cost products.