U.S. Sen. Cory Gardner was among the 28 senators and 20 representatives from both parties to send a letter to the Trump administration on Thursday asking for expanded sanctions against the Chinese government for human rights violations against its Uyghur and Turkic Muslim populations.

“The continued inaction on Global Magnitsky Act sanctions in light of the voluminous evidence showing Chen, in particular, to be a key architect of the current system of internment camps is simply inexcusable,” the members wrote to the secretaries of state, commerce and the treasury. “The Treasury Department should move to approve and implement these sanctions immediately.”

The Global Magnitsky Act authorizes the president to block visas and impose property sanctions on persons responsible for human rights abuses or corruption. Chen refers to Chen Quanguo, Community Communist Party secretary for the northwest autonomous region home to Uyghurs and other ethnic minorities.

The letter mentioned reporting from The New York Times that exposed the communist party referring to ethnic groups as spreading the “virus” of radical Islam. “The system of forced labor that accompanies mass internment,” they wrote, “has effectively turned the region into a massive labor camp that cruelly exploits ethnic minority labor as part of a program of political indoctrination.”

Senators and representatives asked for stronger disclosure requirements to U.S. investors about companies that do business in the autonomous region, where the forced labor is occurring, and to expand the list of imports that U.S. Customs and Border Protection can block.

They further demanded a “strong response” from the administration in freeing family members of U.S. citizens who are detained in China for speaking out against the human rights abuses.