Volkswagen operates its plant in Urumqi, Xinjiang as a joint venture with China's SAIC Motor.

Volkswagen faced a barrage of criticism from campaigners Tuesday after the head of its Chinese business said he saw no sign of forced labor during a visit to the carmaker’s plant in Xinjiang.

Activists and an international group of lawmakers said verifying labor standards in the region was impossible.

Rights groups have documented human rights abuses in Xinjiang since the 2000s, including mass forced labor in detention camps which the United Nations said could constitute crimes against humanity. China has denied any abuses in Xinjiang.