China announced anti-dumping duties of up to 105.4 percent Friday on imports of U.S. chicken products, adding to trade strains with Washington.

The case comes amid mutual accusations of protectionism by Beijing and Washington which both say will hurt efforts to end the global economic downturn.

A preliminary investigation concluded U.S. exports were being sold at improperly low prices that harmed Chinese competitors, the Commerce Ministry said. It said importers must post a bond until a final decision is reached.

Beijing launched the investigation in September after Washington raised duties on imports of Chinese-made tires despite vigorous opposition from China.

The two governments also are embroiled in disputes over access to each other's markets for steel pipes, movies and books and other goods.

U.S. President Barack Obama said this week Washington would take a tougher stand against Beijing in disputes over trade and currency. China's foreign ministry criticized the comments and said its currency controls are not to blame for the country's trade surplus.

The chicken duties take effect Feb. 13 and apply to whole birds, chicken sausage and other products, the Commerce Ministry said. Included are chicken feet, which most Americans throw away but which are a declicacy in southern China.

Companies that appealed the ruling will pay lower duties of 43.1 percent to 80.5 percent, the ministry said. Tyson Foods Inc. will be charged the lowest rate, while Pilgrim's Pride Corp. is at the top end of that range.

Importers that did not appeal will be charged 105.4 percent, the ministry said.