China's anti-dumping investigation into U.S. exports of animal feed could disrupt trade, a U.S. trade group said Friday.

The U.S. Grains Council said in a statement that China's decision this week to open a probe into American exports of distiller's dried grains, a byproduct of corn-ethanol production used for animal feed, was "surprising and could be disruptive to trade."

"China's unusual market and supply volatility over the last two years has resulted in new global trade flows. As trade flows change, it should perhaps not be surprising there would be an adjustment period in response to unprecedented demand," said the group, an influential lobbying arm for the farm industry in the United States.

China's Ministry of Commerce announced Tuesday it had begun looking for evidence of dumping from July 2009 until June 2010, and would also widen the search for harm to China's industry starting from January 2007.

Trade tensions between the U.S. and China have sharpened in the past year over a number of issues, from clean energy to currency. Specific spats have emerged over commodities including tires, auto parts and beef.

Earlier this week, the Obama administration filed a case against China before the World Trade Organization, accusing Beijing of providing unfair government subsidies to Chinese energy companies.

The case arose from a petition by the United Steelworkers union in September, which alleged that Chinese businesses have undercut foreign manufacturers of wind and solar equipment on the international market because of huge government subsidies.