The National Highway Traffic Safety Administration has upgraded its investigation into approximately 65,347 2011-'13 Kia Sorento crossover vehicles after receiving a number of consumer complaints that the sunroof may suddenly shatter.

Safety regulators said there are at least 95 reports of shattered sunroofs so far, based on complaints filed with the automaker and with the NHTSA.

At least 18 reports of minor cuts and scratches have been received, though no crashes have occurred.

"The majority of these claims occurred while the vehicle was in motion," said the NHTSA regarding the probe. "Glass shattering while driving may distract the driver, and the resulting glass particles which enter the passenger compartment may injure occupants."

The NHTSA opened its investigation into the complaints in October.

Only one potential cause for sunroof breakage has been identified by the automaker.

"Kia advises that the Sorento sunroofs have a greater surface area than many other vehicles, potentially making them more susceptible to road debris strikes," NHTSA said. "While (NHTSA) recognizes that the Sorento may be more at risk due to its larger impact area, the rate of reported incidents is concerning. Thus, the investigation has been upgraded to further analyze the scope, frequency and consequence of these failures."

Kia Motors America spokesman James Hope said to Edmunds that only debris and hail have been identified as the cause of sunroof breakage during product investigations.

The automaker will "continue to thoroughly investigate and research this issue and will continue to share its findings with NHTSA," said Hope.

Sorento owners with more questions can reach Kia Consumer Affairs at 1-800-333-4542.

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