The USTR said it will extend a public comment period for the US$200 billion list to Sep 5 from Aug 30 due to the possible tariff rate rise.
In July, the Trump administration introduced 25-percent tariffs on Chinese goods worth $34 billion.
"US pressure and blackmail won't have an effect".
Trump has threatened to slap tariffs on virtually all of China's exports to the United States.
While a poor PMI for one month doesn't necessarily signal a new trend, it does highlight the risk that the trade dispute is starting to hit economic growth.
The U.S. trade war with China just got kicked up another notch.
China's imports from the United States previous year totalled $153.9 billion.
Trump recently threatened to slap punitive tariffs on all Chinese exports to the United States, which amounted to more than $500 billion past year.
The ministerial talks provided a useful occasion to inform the EU's trade partners about the results of last week's meeting between Trump and European Commission President Jean-Claude Juncker, according to a commission official.
While the overall drop to 50.8 in July from June's 51.0 was small, of bigger concern was the slump in the subindex for new export orders, which dropped to 48.4, a fourth consecutive monthly decline.
"It's very hard to see how this doesn't negatively impact all Americans in every walk of life", FDRA president and CEO Matt Priest previously told FN.
Chinese authorities warned earlier that if the dispute escalated, they would adopt unspecified "comprehensive measures". China immediately vowed to retaliate though at the same time urged the U.S. to act rationally and return to talks to resolve the dispute.
In addition, the USA claims that China is stealing intellectual property despite the practice having been tolerated since China entered the World Trade Organization (WTO).
Several American companies, including General Motors, Harley-Davidson, and Whirlpool, have reported significant losses, which they base at least in part on the tariffs imposed by the Trump administration, or on the tariffs other nations imposed as retribution for Trump's tariffs.
Two Trump administration officials told reporters on a conference call that Trump remains open to communications with Beijing.
Geng gave no indication whether the two sides were preparing to resume negotiations.
China's top diplomat on Thursday encouraged the Trump administration to "calm down" amid escalating tariff threats, saying increased rhetoric will not lead to results.
The most obvious is Trump's push to require that autos contain more content made within the NAFTA trade bloc and specifically from countries that pay high wages (that is, not Mexico) to qualify for duty-free status under the agreement.