WASHINGTON — The U.S. Commerce Department imposed new import fees Tuesday on solar panels made in China, finding that the Chinese government is improperly giving subsidies to manufacturers of the panels there.

The Commerce Department said it has found on a preliminary basis that Chinese solar panel makers have received subsidies of 2.9 percent to 4.73 percent. Therefore, the department said tariffs in the same proportions will be charged on Chinese panels imported into the U.S., depending on which company makes them.

The tariff amounts are considered small, but the decision could ratchet up trade tensions between the U.S. and China.

Several U.S. solar panel makers 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, just as President Obama is working to promote renewable energy.

“Today’s announcement affirms what U.S. manufacturers have long known: Chinese manufacturers have received unfair … subsidies,” Steve Ostrenga, CEO of Helios Solar Works in Milwaukee, Wis., said in a prepared statement. The company is a member of a group called the Coalition for American Solar Manufacturing.

On the other side, some U.S. companies argue that low-priced Chinese imports have helped consumers and promoted rapid growth of the industry.

Commerce said it was putting off until May 17 a decision on whether Chinese companies are dumping the solar panels on world markets, selling them below cost.

Trade tensions with China are especially sensitive at a time when the U.S. and other Western economies want to boost technology exports to revive economic growth and reduce high unemployment.

The U.S. and China are two of the world’s biggest markets for solar, wind and other renewable energy technology. Both governments are promoting their own suppliers in hopes of generating higher-paid technology jobs.

The U.S. manufacturers’ complaints have been amplified by the controversy surrounding Solyndra Inc. – a California-based solar panel maker that filed for bankruptcy protection after winning a $500 million federal loan from the Obama administration. Solyndra has cited Chinese competition as a key reason for its failure.

U.S. energy officials say China spent more than $30 billion last year to subsidize its solar industry.