On the Shanghai Futures Exchange, the most-traded copper fell as far as 47,800 yuan ($7,175) a tonne on Wednesday, its weakest since June 23 last year. Zinc was also hard hit, with the metal dropping by its 6 percent downside limit in Shanghai to 20,620 yuan per tonne, the lowest since June 22 last year. It fell as much as 4.8 percent to $2,503 in London, the lowest since June 15, 2017. Shanghai nickel and lead fell more than 2 percent.
Metals slumped in a broad selloff on Wednesday after the United States raised the stakes in a trade war with China with threats of more tariffs.
The Trump administration said it would slap 10 percent tariffs on another $200 billion worth of Chinese imports, raising fears the festering trade dispute between the world's two biggest economies could hit global growth.
"There certainly is going to be pronounced risks mainly because we've now moved on to the tit-for-tat-for-tit phase of it," said Vishnu Varathan, head of economics and strategy at Mizuho Bank in Singapore.
Last week, Washington imposed 25 percent tariffs on $34 billion of Chinese imports and Beijing responded immediately with matching tariffs on the same amount of US exports to China.
"This is going to drag on until they can all come to the table and agree to even the playing field. But the unpredictability of the situation continues to rattle the markets," said Varathan.
US officials released a list on Tuesday of thousands of Chinese imports the Trump administration wants to hit with the tariffs, including hundreds of food products as well as tobacco, chemicals, coal, steel and aluminium.