A dispute over chickens is the latest irritant in trade relations between the world's two largest economies.

Chinese officials Wednesday defended the legality of stiff tariffs on imports of American chickens, a day after the United States filed a formal complaint with the World Trade Organization in Geneva.

U.S. Trade Representative Ron Kirk said there is no legal basis for the year-old tariffs, which range up to 100 percent and have cut U.S. poultry exports to China by 90 percent.

But China's commerce ministry insisted in a statement Wednesday that the tariffs fully comply with WTO rules.

The statement said China will study the U.S. complaint and handle it in accordance with WTO procedures.

China imposed the tariffs in September 2010, apparently in retaliation for U.S. action to limit the import of Chinese tires. China claimed U.S. chicken exporters were sending the poultry to China at unfairly low prices.

Kirk said the United States would prefer to settle the dispute with China amicably and quickly, rather than through a protracted legal process.

Under WTO rules, the two countries will have 60 days to try to resolve the dispute, but if that fails the United States can ask the WTO to consider its complaint.