Asia stock markets have been hit by fears that US President Donald Trump’s plan for tariffs on up to $60bn of Chinese products could trigger a trade war.
Japan’s Nikkei 225 index fell 4.5% and the Shanghai Composite fell 3.6%.
China responded to news of the planned tariffs by saying that while it did not want a trade war, it was “absolutely not afraid” of one.
Mr Trump’s proposed tariffs are a response to allegations of intellectual property theft by China.
The US launched a complaint against China at the World Trade Organization (WTO) on Friday.
Its statement said: “China appears to be breaking WTO rules by denying foreign patent holders, including US companies, basic patent rights to stop a Chinese entity from using the technology after a licensing contract ends.”
“China also appears to be breaking WTO rules by imposing mandatory adverse contract terms that discriminate against and are less favourable for imported foreign technology.”