U.S. regulators have opened an investigation into 2.6 million Teslas after reports of crashes involving the use of company technology that allows drivers to remotely command their vehicle to return to them, or move to another location, using a phone app.

The National Highway Traffic Safety Administration also said Tuesday that Tesla did not report any of the accidents. Tesla is under order to report crashes on “publicly accessible roads” involving vehicles being operated through its autonomous driving technology.

The new investigation follows another probe launched in October looking into the company's “Full Self-Driving” system after getting reports of crashes in low-visibility conditions, including one that killed a pedestrian. That investigation covers 2.4 million Teslas from the 2016 through 2024 model years.

Tesla did not respond to a request for comment from The Associated Press on Tuesday.

One driver filed a complaint after a crash while using Tesla's “Actually Smart Summon” technology and NHTSA is looking into another three similar incidents based on media reports, the NHTSA said. The agency is looking into 12 total incidents reported by users of the technology.

Each of the vehicles failed to detect posts and other parked vehicles, according to the NHTSA.

Regulators say the vehicles struck objects because the users had "too little reaction time to avoid a crash, either with the available line of sight or releasing the phone app button, which stops the vehicle’s movement.”

Shares of Tesla Inc., based in Austin, Texas, slid more than 4% in late afternoon trading Tuesday.

Musk has complained that U.S. regulations are too onerous and are holding back the development of self-driving cars. Ethics experts are worried that once President-elect Donald Trump takes office, Musk will push him to ease oversight of Tesla, which just suffered its first decline in annual sales in more than a decade.

Musk donated an estimated $250 million to Trump's presidential campaign and is a frequent guest at Trump's Mar-a-Lago, vetting cabinet nominees and meeting with foreign heads of state. Trump has put Musk in charge of an advisory group, the Department of Government Efficiency, that will recommend where to cut government expenses and staff at federal agencies and reduce regulation.

The NHTSA said Tuesday it will look into the top speed that Teslas can reach when users deploy its “summons” technology, as well as restrictions on public roads and line of sights requirements. It also said it expects to check for any “connectivity delays" with the app that could result in increased stopping distance.

Tesla’s Model 3 owner’s manual says that its “summons” feature is designed for use only in parking lots and driveways on private property and is disabled on public roads.

The new probe covers 2016-2025 Model S and X vehicles, 2017-2025 Model 3, 2020-2025 Model Y equipped with Tesla's Full Self-Driving driver assistance system.