FILE PHOTO: Chinese Vice Premier Liu He, right, poses with U.S. Treasury Secretary Steven Mnuchin, center, and U.S. Trade Representative Robert Lighthizer, left, before they proceed to their meeting at the Diaoyutai State Guesthouse in Beijing, Wednesday, May 1, 2019. Andy Wong/Pool via REUTERS/File Photo

WASHINGTON (Reuters) - China had backtracked on commitments in trade talks, prompting U.S. President Donald Trump to threaten additional tariffs over the weekend, but Washington would be willing to keep talking if the Chinese changed position, top U.S. trade officials said on Monday.

“Over the course of the last week or so we have seen ... an erosion in commitments by China,” U.S. Trade Representative Robert Lighthizer told reporters. He said China had retreated from specific commitments, a move that would have led to substantive changes in the text of the deal.

“That in our view is unacceptable,” he said.

A delegation from China will be in Washington on Thursday and Friday and Lighthizer said he expected top Chinese negotiator Vice Premier Liu He will attend.

Trump wants to see a deal with substantial structural changes but that is not where the two sides are at the moment, Lighthizer said as he and Treasury Secretary Steven Mnuchin briefed reporters.

Lighthizer said the Chinese pulled back on some commitments reached in the talks over the last week or so and that was what precipitated Trump’s tweet on Sunday promising to raise tariffs on $200 billion worth of Chinese goods to 25 percent from 10 percent by the end of the week.

Mnuchin said it would be unfortunate if the two sides, the world’s biggest economies, could not conclude an agreement and they had hoped to conclude a deal by the end of the week.

If they hear something different from the Chinese this week, Mnuchin said, they will report that to Trump.