If no deal is reached by that date the US has threatened to raise tariffs on Chinese imports by 15-percent, but White House economic adviser Larry Kudlow has said the president would consider extending the trade truce if progress is made during negotiations.

"But at some point, I expect to meet with President Xi.and make the parts of the deal that the group is unable to make", he said, in reference to senior US and Chinese officials in charge of trade negotiations. Leaving the delegation's Beijing hotel Wednesday morning, Mnuchin said he's hoping for "productive meetings".

Observers fear the trade dispute is just one element in the deteriorating relationship between the world's two top economies with top White House officials sharply criticising Beijing for everything from human rights abuses to cyber-warfare.

The U.S. president hasn't been clear about whether he'll sit down to finalize a deal with Xi.

When asked if he will meet Chinese President Xi Jinping at end-March, he said: "Not at this point". Earlier, US President Donald Trump suggested that he might extend the deadline for reaching a trade deal with China beyond March 1st.

A growing number of US businesses and lawmakers hope the tariff increase is delayed while the two sides tackle the hard USA demands for major structural policy changes by China.

Mr Trump said last week that he did not plan to meet Mr Xi before the March 1 deadline.

"The relevant actions of the USA warships violated Chinese sovereignty, and undermined peace, security, and order in the relevant sea areas", Chinese Foreign Ministry spokeswoman Hua Chunying said on Monday, South China Morning Post reported.

USA advisers have previously called March 1 a "hard deadline" for the talks.

The latest round of talks in Beijing kicked off on Monday with discussions among deputy-level officials to try to work out technical details, including a mechanism for enforcing any trade agreement. Trump noted that a large United States delegation is now in China, and said things were going well with the negotiations.

China's Foreign Ministry referred questions on the talks to the Ministry of Commerce, which did not respond to a request for comment.

"The hardliners seem loath to settle for a deal that represents anything less than total capitulation by China on all USA demands", he said.

Washington is expected to keep pressing Beijing on long-standing demands that it make sweeping structural reforms to protect American companies' intellectual property, end policies aimed at forcing the transfer of technology to Chinese companies, and curb industrial subsidies.