Authorities in Brazil said Friday they are probing Chinese auto giant BYD and one of its contractors for suspected "trafficking" of Chinese workers building a factory in the South American country.

Chinese workers at a construction site in Brazil for a factory owned by China's electric vehicle producer BYD are victims of human trafficking, Brazilian labor authorities said on Thursday in a growing controversy in BYD's biggest overseas market.

The Chinese automaker is known for using cheap labor to reduce the price of its EVs, with Brazil becoming its largest overseas market.