(Reuters) -Tesla is recalling 9,136 Model X sports utility vehicles over a trim on the roof that could separate, increasing the risk of a crash, the National Highway Traffic Safety Administration (NHTSA) said.

This marks a rare physical recall for the Austin, Texas-based automaker, which usually fixes issues in its vehicles through over-the-air software updates.

Tesla recalled nearly 2.6 million vehicles due to safety concerns in the first six months of the year, only behind Ford Motor which has recalled about 3.6 million vehicles in the U.S., according to recall management platform developer Bizzycar.

"The front and center roof cosmetic trim pieces may be adhered to the vehicle without primer. As a result, one or both pieces of trim may separate from the vehicle," the U.S. auto safety regulator said in a letter dated Aug. 20.

If the trim's adhesion to the surface lacks primer, the part could separate from the vehicle over time, creating a road hazard and increasing the risk of a crash, NHTSA's safety recall report said.

The letter said the EV maker will test adhesion of the roof trim and reattach the trim pieces as necessary at no cost to owners of the vehicles.

(Reporting by Akash Sriram in Bengaluru; Editing by Varun H K)