Two US senators requested a federal investigation of Tesla's statements about its Autopilot driver assistance system Wednesday, asserting in the wake of multiple crashes that the automaker's exaggerations have put consumers at risk.

The letter to the Federal Trade Commission concerning "Tesla's misleading advertising" comes two days after another federal agency launched a probe into Autopilot.

Tesla and Chief Executive Elon Musk's "repeated overstatements of the vehicles' capabilities -- despite clear and frequent warnings -- demonstrate a deeply concerning disregard for the safety of those on the road and require real accountability," Democratic senators Richard Blumenthal and Ed Markey wrote.

"We urge you to swiftly open an investigation into Tesla's repeated and overstated claims about their Autopilot and Full Self-Driving features and take appropriate enforcement action to prevent further injury or death as a result of any Tesla feature," they said in the letter to FTC Chair Lina Khan.

The Autopilot system assists with steering and automatic braking and can be employed to help drivers navigate past slow cars, according to Tesla's website, which says the system's features "require active driver supervision and do not make the vehicle autonomous."

Two US senators requested a federal probe of claims about Autopilot by Tesla and its chief executive, Elon Musk
Two US senators requested a federal probe of claims about Autopilot by Tesla and its chief executive, Elon Musk AFP / Brendan Smialowski

However, the senators pointed to other Tesla marketing material that they said contradicted its disclaimer, sowing confusion and giving consumers false confidence in the system.

A Tesla 2019 YouTube video seen more than 18 million times is titled "Full Self-Driving" and shows a driver not touching the wheel as his car bows and weaves through highway traffic and smaller roads, stopping at red lights.

The senators also cited comments from Musk saying the company would soon reach full autonomy, a benchmark not expected until 2025, according to the National Highway Traffic Safety Administration (NHTSA).

"Tesla drivers listen to these claims and believe their vehicles are equipped to drive themselves -- with potentially deadly consequences," the senators said.

The letter came two days after the NHTSA launched a probe into Autopilot after identifying 11 crashes involving the driver assistance system, including one fatal crash and seven that resulted in injuries to 17 people.

Tesla shares, which fell the last two days following the NHTSA announcement, rose 3.5 percent to $689.16 in late-morning trading.