A group of U.S. senators wrote to Scottsdale-based Universal Electronics on Wednesday about concerns over the company’s alleged mistreatment of Uyghur Muslims in China.

The congressional letter cites a Reuters report that says the electronics company struck a deal with Chinese authorities to transport hundreds of Uyghur workers to its plant in southern China where workers live in segregated dormitories and are surveilled by police. U.S. senators cite State Department findings that Chinese authorities use threats of physical violence, forcible drug intake, physical and sexual abuse, and torture to force detainees to work. The Arizona company has responded by saying it has ended its relationship with the agency that hired the Uyghur workers — and looks forward to cooperating with the senators.

UEI has been asked to provide information by Nov. 5 about the 2019 agreement with the Xinjiang government, including how many Uyghurs were employed in China and documented proof of the company's claim that the labor was not forced.

The senators also asked for details of employee training programs related to forced labor and human trafficking, records of audits of facilities in China, and the content of any disclosure to shareholders about the use of transferred Uyghur laborers.

UEI, a public company listed on NASDAQ, sells to Sony, Samsung, LG, Microsoft and other companies, said it does not conduct independent due diligence on where and how its workers are trained in China, but rather the arrangement is vetted by a third-party agent, contracted with the Xinjiang government.

A spokesperson issued on Friday a statement to KJZZ: "We look forward to working with Chairman Menendez, Ranking Member Rubio and Sen. Merkley on the questions they raised in the letter. UEI made the decision last week to end its relationship with the staffing agency that hired these workers based on feedback on how to best secure its supply chain and in light of ongoing regulatory and legislative changes globally."