Chinese stock markets tumbled on Monday after US President Donald Trump threatened new tariffs on China, putting a trade deal in doubt.
He said on Twitter the US would more than double tariffs on $200bn (£152bn) of Chinese goods on Friday and would introduce fresh tariffs.
Recent comments had suggested both sides were nearing a trade deal.
A Chinese delegation was due to travel to Washington this week for talks aimed at ending the trade war.
US media has reported that China is now considering cancelling those talks, led by Vice-Premier Liu He, that were scheduled to resume on Wednesday.
Some reports said the Chinese were due to send a 100-person delegation to the negotiations.
The Chinese government has yet to officially comment on Mr Trump’s tweets.
In China, Hong Kong’s Hang Seng index dropped 3.7%, while the Shanghai Composite plunged 5.3%.
US stock futures pointed to a lower open on Wall Street.
What did Mr Trump say?
The US president tweeted that tariffs of 10% on certain goods would rise to 25% on Friday, and $325bn of untaxed goods could face 25% duties “shortly”.
“The Trade Deal with China continues, but too slowly, as they attempt to renegotiate. No!” he tweeted.
After imposing duties on billions of dollars worth of one another’s goods last year, the US and China have been negotiating and in recent weeks, appeared to be close to striking a trade deal.
Last week US Treasury Secretary Steven Mnuchin described talks held in Beijing as “productive”.
What will the tariff rise affect?
Mr Trump’s latest move will raise duties on more than 5,000 products made by Chinese producers, ranging from chemicals to textiles and consumer goods.
The US president originally imposed a 10% tariff on these goods in September that was due to rise in January, but postponed this as negotiations advanced.
However, both US and international firms have said they are being harmed by the trade war.
Fears about a further escalation caused a slump in world stock markets towards the end of last year.