New Delhi : Sun Pharmaceutical Industries said the United States health regulator has issued an observation letter after the completion of its Halol facility inspection.

The company's "Halol facility has undergone an inspection by the US Food and Drug Administration (USFDA) recently. The inspection was completed on December 1, 2016. A Form 483 observation letter was issued by the USFDA post the inspection," Sun Pharmaceutical Industries said in a BSE filing.

However, the company did not disclose the number or nature of the observations made by the FDA.

"We are currently in the process of responding to the said letter to the USFDA within the stipulated timeline of 15 days," it added.

Sun Pharma was earlier issued a warning letter by the USFDA for its Halol facility in December 2015. The letter followed inspection of the facility in September 2014 by FDA inspectors.

Post the September 2014 inspection, the USFDA had withheld future product approvals from the Halol facility.

The company has been making efforts to make the Halol plant CGMP-compliant again.

As per the USFDA, observations are made in Form 483 when investigators feel that conditions or practices in the facility are such that products may become adulterated or render injurious to health.

The FDA Form 483 notifies the company's management of objectionable conditions.

Shares of Sun Pharmaceutical Industries were trading 5.15 per cent down at Rs 669.65 on BSE.