Republican attorneys general from 16 U.S. states have asked the Securities and Exchange Commission to audit China-founded fast-fashion retailer Shein's supply chain for the use of forced labor ahead of a potential initial public offering by the company.

Amid rising friction between Washington and Beijing, the letter, sent to the SEC last week, adds to pressure on Shein as China hawks in Congress target Chinese firms that do not align with U.S. foreign policy goals.

Shein, which sells $7 dresses and $5 home goods in more than 150 countries, has moved its headquarters to Singapore but manufactures most of its products in China.