President Donald Trump and top US officials say a trade truce with China will lead to structural changes in Beijing's economic policies, including lower tariffs, lower non-tariff barriers and more market access for American companies.
Trump and Chinese President Xi Jinping agreed to hold off on new tariffs during talks in Argentina on Saturday, declaring a truce following months of escalating tensions on trade and other issues.
On Sunday, Trump tweeted that China had agreed to cut import levies on American-made cars.
"My meeting in Argentina with President Xi of China was an extraordinary one. Relations with China have taken a BIG leap forward! Very good things will happen," Trump tweeted on Monday.
Chinese regulators did not respond to requests for comment on Trump's tweet on car tariffs. Neither country had mentioned car tariffs in their official read-outs of the Trump-Xi meeting.
At a dinner lasting two and a half hours, the US agreed at the weekend not to raise tariffs further on January 1, while China agreed to purchase more agricultural products from US farmers immediately.
The two sides also agreed to negotiate over the next 90 days to resolve issues of concern raised by the US including intellectual property protection, non-tariff trade barriers and cyber theft.
US Treasury Secretary Steven Mnuchin said on Monday there was a clear shift in tone at Buenos Aires from past discussions with Chinese officials, as Xi offered a clear commitment to open China's markets to US companies.
"This is the first time that we have a commitment from them that this will be a real agreement," Mnuchin told CNBC television, adding that the administration would know "very quickly" whether a deal can be documented.
"We absolutely need something concrete over these 90 days," Mnuchin added. "This is not going to be something where there's just soft commitments that get kicked down the road."
The truce boosted global markets on Monday with world stocks up nearly 1 per cent.
Mnuchin said the negotiations with China would be led by Trump, with an "inclusive team" of administration officials, including himself and other cabinet officials.
White House trade adviser, Peter Navarro, said, however that the talks would be led by US Trade Representative Robert Lighthizer - a shift from past practices where Mnuchin had a lead role.
The White House has said the existing 10 per cent tariffs on $US200 billion ($A271 billion) worth of Chinese goods would be lifted to 25 per cent if no deal was reached within 90 days, once again setting the clock ticking.
Speaking in Beijing, Chinese Foreign Ministry spokesman Geng Shuang reiterated comments from the government's top diplomat State Councillor Wang Yi who said on Saturday the ultimate goal was the lifting of all tariffs.
Australian Associated Press