U.S. Treasury Secretary Steven Mnuchin leaves a hotel with members of his negotiation team on the way to high-level trade talks in Beijing on Feb. 14, 2019.

U.S. Treasury Secretary Steven Mnuchin said he was looking forward to trade talks with China on Thursday, as discussions in Beijing moved to a higher level in a push to de-escalate a tariff war ahead of a March 1 deadline for a deal.

The talks, scheduled to run through Friday, follow three days of deputy-level meetings to work out technical details, including a mechanism for enforcing any trade agreement.

"Looking forward to discussions today," Mnuchin told reporters without elaborating as he left his hotel.

He and U.S. Trade Representative Robert Lighthizer opened the meetings shortly afterward at the Diaoyutai state guest house with Chinese Vice Premier Liu He, the top economic adviser to Chinese President Xi Jinping.

U.S. tariffs on $200 billion worth of imports from China are scheduled to rise to 25 percent from 10 percent if the two sides don't reach a deal by the deadline, increasing pressure and costs in sectors from consumer electronics to agriculture.

U.S. President Donald Trump told reporters on Wednesday that the negotiations had been progressing "very well".

Trump's advisors have described March 1 as a "hard deadline", and the president has said a delay was possible though he preferred not to do so. But, a Bloomberg report on Thursday cited sources saying he was considering pushing back the deadline by 60 days to give negotiators more time.

Trump has said he did not expect to meet with Xi prior to March 1, but White House Press Secretary Sarah Sanders has raised the possibility of a meeting between the leaders at the president's personal retreat at Mar-a-Lago in Florida.

U.S. Department of Agriculture Deputy Secretary Stephen Censky said on Wednesday that the two presidents were expected to meet "sometime in March," but no dates were set.

The Chinese government has offered few details about the state of negotiations this week.