Beijing said in response that it would only join the talks if the U.S. reduced its arsenal to match China's much smaller nuclear deterrent, prompting Washington to again issue a fresh invitation to the talks on Thursday.
The United States on Thursday took its first major action to stop "horrific" abuses against China's Uighurs and other Turkic Muslims, slapping sanctions on several senior officials.
"The United States will not stand idly by as the CCP carries out human rights abuses targeting Uyghurs, ethnic Kazakhs and members of other minority groups in Xinjiang, to include forced labor, arbitrary mass detention and forced population control, and attempts to erase their culture and Muslim faith", Secretary of State Mike Pompeo said in a statement announcing sanctions from the State Department.
The move marks the latest in a deteriorating relationship between the USA and the Chinese, coming on top of the spread of the coronavirus - which originated in Wuhan, China - and the Chinese incursion into freedoms in Hong Kong.
Chen made his mark swiftly after taking the top post in Xinjiang in 2016, with mass "anti-terror" rallies conducted in the region's largest cities involving tens of thousands of paramilitary troops and police.
The move marked the first time since the USA established diplomatic ties with China in 1979 that Washington has sanctioned a member of China's elite Politburo, comprising the party's top two dozen officials, say scholars of Chinese politics.
Treasury Secretary Steven Mnuchin had also raised objections to the Treasury sanctions, especially against a Politburo member, out of concerns they could further damage U.S.
The Treasury Department also imposed sanctions on the security bureau as an institution, pointing to its sweeping digital surveillance of Uighurs and other minorities.
Secretary of State Mike Pompeo released a statement about the sanctions claiming that the United States is committed to action.
Last month, Trump signed legislation, passed with overwhelming support from Congress, mandating that individuals, including Chen, face sanctions for oppressing Uighurs. Their family members may also be subject to the restrictions.
Last year, the BBC saw leaked documents that showed 15,000 people from southern Xinjiang were sent to the camps in one week alone.
Chinese officials deny the detention facilities in Xinjiang are "concentration camps", describing them instead as "vocational education centres" where "students" learn Mandarin and job skills in an effort to steer them away from religious extremism following deadly attacks and riots.
Foreign Ministry spokesperson Zhao Lijian told reporters the US was "neither serious nor sincere" in the proposed negotiations and should instead respond to Russia's call for an extension to the existing New START treaty limiting the number of nuclear warheads.