U.S. auto safety regulators said Tuesday they are opening a probe into 50,000 Tesla Model X vehicles after receiving two complaints reporting front seat belt failures.

The National Highway Traffic Safety Administration said the preliminary evaluation covers 2022-2023 model year vehicles over reports of failures of the front seat belt to remain connected to the seat belt anchor pretensioner while driving.

Both vehicles had insufficiently connected anchor linkages and neither incident involved vehicle collision, the agency said.