San Francisco, Jan 10 : The US National Highway Traffic Safety Administration (NHTSA) has asked Tesla about a tweet by its CEO Elon Musk that the electric car-maker will remove the driver monitoring warning from its Full Self-Driving (FSD) software. An NHTSA spokesperson confirmed to The Verge that it has reached out to Tesla to gather information about the Musk tweet. The driver monitoring function warned users to keep their hands on the steering wheel while using the FSD mode. On December 31 last year, a user tweeted that "users with more than 10,000 miles on FSD Beta should be given the option to turn off the steering wheel nag". Musk replied the next day: "Agreed, update coming in January." FSD, currently available to everyone in North America who has purchased the software option, allows users to access Autopilot's partially automated driver-assist system on city streets and local roads. "Tesla Full Self-Driving Beta is now available to anyone in North America who requests it from the car screen, assuming you have bought this option. Congrats to Tesla Autopilot/AI team on achieving a major milestone!" the Tesla CEO had tweeted in November. The rollout of FSD came at a time when Tesla faces a criminal investigation from the US Department of Justice over potentially false claims related to Autopilot, the company's advanced driver assistance system. In September, a Tesla owner sued the electric car maker, saying the company and its CEO are "deceptively and misleadingly" marketing the Autopilot and "Full Self-Driving" software. Musk has come under heavy scrutiny on the controversial Autopilot advanced driver assistance system that has allegedly killed many, with both federal and state regulators turning up the heat on the electric car-maker. The NHTSA also upgraded its investigation from a preliminary evaluation to an engineering analysis, asking Tesla to answer questions about its cabin camera as part of a probe into 830,000 vehicles that include Autopilot. /IANS