Chinese and US negotiators are attempting to salvage a trade deal just hours before fresh US tariffs are due to come into force.
US President Donald Trump says the two sides were close to reaching a deal but China attempted to renegotiate.
The US is shortly due to raise tariffs on $200bn (£152bn) of Chinese goods, while China says it will retaliate.
The International Monetary Fund (IMF) said the row poses a “threat to the global economy”.
“As we have said before, everybody loses in a protracted trade conflict,” the body which aims to ensure global financial stability said in a statement, calling for a “speedy resolution”.
The Chinese delegation, led by Vice-Premier Liu He, is meeting US Trade Representative Robert Lighthizer and Treasury Secretary Steven Mnuchin.
President Trump also said he received a “beautiful letter” from Chinese counterpart Xi Jinping and that they would probably speak soon.
China has been a frequent target of Donald Trump’s anger, with the US president criticising trade imbalances between the two countries and Chinese intellectual property rules he says hobble US companies.
Ahead of the discussions, he told a rally China had “broke the deal”.
On top of the new tariffs, due to come into force at 00:01 EDT (04:01 GMT) on Friday, he says he is also taking steps to authorise new tariffs on another $325 billion in Chinese imports.
What exactly sparked the US president’s actions, which apparently took China by surprise, is unclear.
