The U.S. National Highway Traffic Safety Administration has ordered Hyundai to recall 978,000 Sonatas due to defective seatbelts, the carmaker said Thursday.

The Sonatas were manufactured at Hyundai's plant in Alabama between 2011 and 2014 and the recall will start next month.

The problems were first raised in September last year centering on 2013 Sonatas, when the seatbelts in the front seats came loose during collisions.

AP quoted a Hyundai staffer as saying a U.S. government investigation showed that the seatbelt hooks may not be fastened completely due to problems in the manufacturing process and that a "minor injury" had occurred due to the defect.

Hyundai said the recall will involve free repairs at service centers. It added there were no problems with Sonatas sold in Korea because a different manufacturer supplies the parts.

