US in China car import tariff row
The United States has complained to the World Trade Organization about the level of China's import duties on large-engined US-made cars.
About 80% of US vehicle exports to China, valued at $3bn (£1.94bn) a year, will attract the import tariffs.
Washington thinks the tariffs, which could add as much as 21.5% to the price of a luxury car, are unfair.
The WTO, based in Geneva, said it had received formal notification of the complaint on Thursday.
The duties will primarily affect US manufacturers Chrysler and General Motors, potentially adding 15% to the cost of a Chrysler Jeep Grand Cherokee or 21.5% to the cost of General Motors' Cadillac CTS, for example.
In a statement, Ron Kirk, the US trade representative, said: "As we have made clear, the Obama administration will continue to fight to ensure that China does not misuse its trade laws and violate its international trade commitments to block exports of American-made products.
"American auto workers and manufacturers deserve a level playing field and we are taking every step necessary to stand up for them."
The US complaint coincided with President Barack Obama's campaigning visits to the carmaking states of Ohio and Michigan, in advance of November's presidential elections.