At the time, Kia did not recall its vehicles, which share the same "Theta II" engines. In March 2017, Hyundai expanded its original U.S. recall to 572,000 Sonata and Santa Fe Sport vehicles with those Theta II engines, citing the same issue involving manufacturing debris. On the same day, Kia also recalled 618,000 Optima, Sorento and Sportage vehicles, all of which use the same engine. Last month, the Center for Auto Safety, which has petitioned NHTSA to demand the recall of additional vehicles, told Congress that Kia and Hyundai must recall more vehicles at risk of fires after reports of 300 fires not the result of a collision. On Monday, Senator Richard Blumenthal, a Democrat, asked NHTSA to launch a safety defect investigation into Hyundai and Kia vehicles with the "Theta II" engines and order an immediate recall of vehicles (This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)