WASHINGTON (Reuters) - China's fast-growing direct investment in the United States has created jobs and helped some firms and localities, but the security and economic risks posed by the large Chinese state role made such investment a "potential Trojan horse," a congressional advisory panel said in a study on Wednesday.

The study, commissioned by U.S.-China Economic and Security Review Commission, found that Chinese-owned firms in the United States added between 10,000 and 20,000 workers in the past five years and helped shore up financially troubled U.S. firms.

At the same time, China's foreign direct investment (FDI) is spearheaded by state-owned enterprises that enjoy government subsidies and other market-distorting policies that support industrial policy and non-market goals of the Chinese government, it said.

"Based on this juxtaposition, some will conclude that Chinese FDI in the United States is a potential Trojan horse," the report concluded.

Estimates by private economists put Chinese direct investment in the United States at $30 billion through the end of 2011, while official estimates count $5.8 billion through 2010. The number is expected to increase rapidly, said the study.

"These entities are potentially disruptive because they frequently respond to policies of the Chinese government, which is the ultimate beneficial owner of U.S. affiliates of China's SOE (state-owned enterprises)," the report warned.

The ample flow of subsidies to state-owned enterprises from the national and local governments and state-owned financial institutions "raises the possibility that Chinese largesse could determine market outcomes for purchases of U.S. businesses," it said.

The study - conducted for the commission by consultants Capital Trade Inc. in Washington - also pointed to economic security and national security risks that have colored U.S. debate on Chinese investment and caused lawmakers and officials to question if not reject several recent high-profile deals. Continued...