HONG KONG -- Automakers including Toyota, General Motors, Tesla and Volkswagen could be exposed to forced labor in Xinjiang through a key metal used in their cars, according to a new Human Rights Watch report.

Aluminum, crucial to the manufacture of electric vehicles, is used in automobile frames, engine blocks and battery foils. More than 15% of China's production of the metal comes from the western autonomous region of Xinjiang, where Chinese authorities stand accused of human rights abuses against Uyghurs and other Turkic Muslims, a charge long denied by Beijing.