Toyota Motor Corp. is recalling approximately 550,000 vehicles in the United States due to a defect involving seat-backs, the National Highway Traffic Safety Administration announced.

The recall affects multiple Toyota models, though specific vehicle models and model years were not detailed in the initial announcement. The defect appears to be related to the seat-back mechanism, which could potentially pose safety risks to vehicle occupants.

The National Highway Traffic Safety Administration, which oversees vehicle safety recalls in the United States, made the announcement regarding Toyota's latest recall action. NHTSA typically requires automakers to notify vehicle owners and provide free repairs when safety defects are identified.

Toyota has faced various recall situations in recent years as part of the automotive industry's ongoing focus on vehicle safety. The company, like other major automakers, regularly works with federal safety regulators to identify and address potential defects in their vehicle fleets.

Vehicle owners affected by the recall will typically receive notification by mail with instructions on how to schedule repairs at authorized Toyota dealerships. The repairs are generally provided at no cost to the vehicle owner as required by federal regulations.