The Trump administration is “calling black white” and resorting to “lame arguments,” China’s Foreign Ministry spokesman Geng Shuang said at a press briefing on Tuesday, after the Trump administration’s top trade authority criticized a “white paper” released by Beijing over the weekend.

The US is “disappointed” that China released the paper to play a “blame game misrepresenting the nature and history” of trade talks, a statement from the Office of the US Trade Representative said.

Geng retorted that Beijing’s position paper has “completely and accurately restored the process of the consultations and stated the facts and truths,” according to Xinhua.

The US response reiterated the account made by top negotiators, Trade Representative Robert Lighthizer and Treasury Secretary Steven Mnuchin, that Beijing backtracked on key concessions in virtually every chapter of a long-negotiated agreement.

“Following months of hard work and candid and constructive discussions, the parties had reached agreement on a number of important matters.  In wrapping up the final important issues, however, the Chinese moved away from previously agreed-upon provisions,” the statement said.

The back-and-forth adds little cause for optimism as markets brace for a drawn-out trade conflict. The consensus among analysts has moved from the expectation that both sides will reach a deal “because it is in their interests” to a fear that it is becoming increasingly difficult from a political standpoint for either side to make concessions.

While Beijing has cranked up the volume of domestic political criticism of the US position, something that leaders had been cautious about doing until recently, they have made preconditions for talks to resume which appear to be beyond what the Trump administration will be willing to accept.