The US has accused China of illegally subsidising rice, corn and wheat farmers, adding agriculture to a growing list of Washington's concerns over Chinese overproduction and distortion of global markets.
The launch on Tuesday of a new World Trade Organisation case comes as President Barack Obama is campaigning to get a vast new Pacific Rim trade deal ratified by Congress later this year and selling it as a vital element of America’s strategic response to China’s economic rise.
It also comes amid global concerns about China’s industrial overcapacity and a heated US presidential election in which global trade and China’s impact on the US economy have been central issues.
