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.

BYD and contractor Jinjiang Group have agreed to assist and house the 163 workers in hotels until a deal to end their contracts is reached, Brazil’s Labor Prosecutor’s Office said in a statement after meeting representatives from both firms.

The brief statement did not provide details on how prosecutors had reached their conclusion. BYD and Jinjiang did not immediately respond to requests for comment on Friday. Jinjiang rejected the Brazilian authorities’ assessment on Monday that the workers at the site in the eastern state of Bahia were operating under “slavery-like conditions”.