China has decried a US decision to impose steep duties on Chinese-made cold-rolled flat steel.

China's Commerce Ministry says the United States employed unfair methods during its anti-dumping investigation. The US Commerce Department says  new duties will increase import prices on Chinese-made steel products by more than five-fold. China has filed a suit with the World Trade Organization to settle the dispute.

The US has taken a number of measures to protect its struggling domestic steel industry in recent months. But China's Commerce Ministry says resorting to protectionism will not solve the problem.