China has warned that it does not want a trade war with the US, but will not sit idly by if its economy is hurt.
Zhang Yesui, spokesperson for China’s National People’s Congress, made the comments amid controversy over Donald Trump’s announcement of tariffs on steel and aluminium imports.
The US president has also threatened to impose a tax on EU-made cars, and earlier said "trade wars are good".
US trading partners, the IMF and the WTO have strongly criticised his moves.
Mr Trump has decried the "$800 Billion Dollar Yearly Trade Deficit because of our ’very stupid’ trade deals and policies", and vowed to end it.
On Thursday, he said steel imports would face a 25% tariff and aluminium 10%.
Then came Saturday’s threat on EU-made cars.
In January, he had already announced tariffs on solar panels and washing machines.
China’s Zhang Yesui said it was natural that "some friction will exist" between the US and China, given the volume of trade between them surpassed 580bn last year.
But he said China would take "necessary measures" if its interests were hurt.