US President Donald Trump announced on Thursday that the US would apply a new tariff of 10 per cent on about $300 billion worth of products from China beginning September 1.
Mr Trump tweeted amid slow-moving talks with China that negotiations would continue.
But he blamed China for not stopping the sale of the opioid fentanyl to the US or buying large quantities of farm goods such as soybeans.
Stocks immediately tumbled on the news. The Dow Jones Industrial Average, which had been up nearly 300 points earlier, was down nearly 200 soon after the president's tweets.
The US has already applied tariffs of 25 per cent on $250bn worth of goods from China.
Beijing retaliated with tariffs on $110bn in American goods, including agricultural products, in a direct shot at Mr Trump supporters in the US farm belt.
Mr Trump’s threats come after a US delegation returned to Washington from what the White House called “constructive” trade talks.
The negotiations were expected to resume in Washington in September, although dates were not announced.
Mr Trump also tweeted: “We look forward to continuing our positive dialogue with China on a comprehensive trade deal, and feel that the future between our two countries will be a very bright one.”
The world’s two biggest economies are locked in a trade war over US claims that Beijing uses tactics including stealing trade secrets and forcing foreign companies to hand over technology in a bid to overtake American technological dominance.
Talks broke down in May after the US accused the Chinese of reneging on commitments.
