Uber is facing a criminal investigation by the US government over its use of technology that helps drivers avoid officials trying to clamp down on the ride-sharing firm.
Uber is accused of using the software, known as "Greyball", to evade local regulators in regions where the company was not yet allowed to operate.
It is claimed Uber used the technology in places such as US city Portland to identify transport officials and prevent them from booking a ride.
Uber declined to comment on the investigation, which was launched by the US Justice Department. It told Portland authorities that Greyball was used "exceedingly sparingly" in the city before regulators approved its service in 2015.
A Californian grand jury has asked for documents explaining where the Greyball technology, which was first uncovered by the New York Times, was used and how it worked, according to Reuters. Uber has reportedly hired law firm Shearman & Sterling to conduct an internal investigation.
