Both China and Russia are concerned that thousands of citizens who left to fight with terror organizations in Syria could return home to stoke radicalization, a congressionally appointed panel said in a report.

The US-China Economic and Security Review Commission’s report indicates that Beijing in particular is worried that an influx of fighters returning home from the Syrian battlefield could sow insurgent activity along critical stretches of planned Chinese infrastructure investment.

The report said the prospect of radicalization among members of the Muslim Uighur minority in the Xinjiang region "is of particular concern to the Chinese government because the region is a crucial hub" for China's Belt and Road Initiative, which has used railway, port, and construction investments to woo Middle Eastern nations. The initiative has stoked concerns at the Pentagon about threats to American military technology.  

Chinese officials have claimed that up to 5,000 Uighurs are fighting in Syria, according to the report, but those figures have not been verified by American government agencies or independent experts, who indicate the actual number of foreign fighters may be lower.