US tariffs on $34bn (£18.2bn) of Chinese goods have gone into effect, opening the way for an outright trade war between the two economic giants.
The US had said it would impose the 25% levy from midnight Washington time (04:01GMT) – China is expected to retaliate in kind.
The tariffs mark a significant escalation in the trade dispute between the world’s two biggest economies.
The row has caused turbulence on the world’s stock markets.
There are fears it could hurt global trade and growth.
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The move is part of Mr Trump’s protectionist agenda, which has undermined the free trade policies that have shaped the global exchange of goods in recent decades.
Ahead of the planned tariffs coming into effect, China said the US was “opening fire on the entire world, including itself”.