BEIJING (Reuters) – Beijing is insisting U.S. tariffs must be rolled back as part of any phase one trade deal with Washington, China’s Global Times newspaper said on Sunday citing unnamed sources, amid continued uncertainty on whether the two sides can strike a deal.

“A US pledge to scrap tariffs scheduled for December 15 cannot replace the rollbacks of tariffs,” the newspaper said in a tweet, referring to an additional round of tariffs on Chinese imports to be implemented in the absence of a trade deal.

The Global Times is published by the People’s Daily, the official newspaper of China’s ruling Communist Party.

On Tuesday, U.S. President Donald Trump said Washington was in the “final throes” of a deal aimed at defusing a 16-month trade war with China, a few days after Chinese President Xi Jinping had expressed his desire for a trade agreement. Top trade negotiators for both countries also spoke again and agreed to continue working on the remaining issues.

Trade experts and people close to the White House told Reuters last month, however, that signing of a phase one agreement may not take place until the new year as China pressed for more extensive rollbacks of tariffs. An agreement was initially expected to be completed by the end of November.

U.S. Senate Finance Committee Chairman Chuck Grassley told reporters on Tuesday that Beijing invited U.S. Trade Representative Robert Lighthizer and Treasury Secretary Steven Mnuchin for in-person talks in Beijing.

Grassley said Lighthizer and Mnuchin were willing to go if they saw “a real chance of getting a final agreement”.

A source familiar with the trade talks also told Reuters that U.S. officials could travel to China after Thursday’s Thanksgiving holiday in the United States.