US Trade Ambassador Katherine Tai on Wednesday remained noncommittal about what actions Washington might take if China failed to live up to the commitments made under a 2020 trade agreement.
"We are holding them accountable," she told reporters. "We're in negotiations right now."
The "phase one" deal signed in January 2020 under former president Donald Trump included a pledge for Beijing to buy an additional $200 billion of American goods, including energy, agricultural and manufactured products, through 2021 in order to reduce the trade imbalance between the two countries.
But trade experts said China is far from meeting the targets, in part due to the disruptions caused by the Covid-19 pandemic.
Asked what will happen in early 2022, Tai said: "That's the million-dollar question."
But she said she is "optimistic" about the discussions between the world's top economic powers
"I don't want anybody in this room thinking that we are not getting traction with our Chinese counterparts," Tai said.
Relations between the two nations deteriorated under Trump, who imposed tariffs on $370 billion worth of Chinese products in 2018, citing trade practices Washington deemed "unfair."
But many US companies have criticized the levies, saying they drive up costs, since importers bear the brunt.
In early October, Tai held just her second meeting with her Chinese counterpart, Vice Premier Liu He, but said President Joe Biden would keep the punitive duties in place.
In her comments on Wednesday, Tai reiterated the importance of the bilateral trade but gave no indication of a timetable for the discussions.
"The US-China trade relationship is enormous, enormously consequential. It's also a big piece of the overall US-China relationship," she said.