US President Donald Trump on Sunday increased the pressure on China to reach a long-sought trade deal by announcing a huge increase of American tariffs on certain Chinese goods.
Mr Trump delayed the tariff surges earlier this year as talks with China appeared to be going positively.
His announcement casts into doubt expectations that China and the US were close to reaching a deal to end a months-long trade war that has slowed global growth and disrupted markets.
Mr Trump said that tariffs would increase to 25 per cent on a reported $200 billion (Dh734.64 billion) of goods on Friday and that more Chinese goods would face extra tariffs.
"The trade deal with China continues but too slowly, as they attempt to renegotiate. No," he tweeted.
The trade discussions are due to resume this week, with Chinese Vice Premier Liu He set to travel to Washington.
Hopes had risen in April after Treasury Secretary Steve Mnuchin said talks in Beijing were productive.
As recently as Friday, Mr Trump said talks with China were going well.
Last week, industry sources said they believed the talks were close to reaching a conclusion, Reuters reported.
Mr Mnuchin had said he hoped that the US negotiating team would soon be able to recommend a deal to Mr Trump or tell him that one could not be reached.
The administration has been insisting on a means to ensure that China follows through on any promises to buy more American goods.
Officials have said both sides are expected to introduce enforcement staff to police the agreement.
White House economic adviser Larry Kudlow told Fox News that the president's tweet was a warning to the Chinese.
"The president is, I think, issuing a warning here, that, you know, we bent over backwards earlier, we suspended the 25 per cent tariff to 10 and then we’ve left it there," Mr Kudlow said.
"That may not be forever if the talks don’t work out."
Financial markets reacted negatively. S&P 500 e-minis were down 54.75 points, or 1.86%, while Nasdaq 100 e-minis were down 168 points, or 2.14%, and Dow e-minis were down 484 points, or 1.83%.
"Raising tariffs means raising taxes on millions of American families and inviting further retaliation on American farmers," said Christin Fernandez, a spokeswoman for the Retail Industry Leaders Association.
