The US Food & Drug Administration has issued a warning letter to Ranbaxy Laboratories' fully-owned US subsidiary Ohm Laboratories for violating manufacturing practices.

Ranbaxy, one of the India’s leading pharmaceutical companies, said the letter dated December 21 had concerns over Ohm’s liquid manufacturing facility in Gloversville, New York.

Ohm Laboratories is one of the three US-based manufacturing sites of Ranbaxy.

The warning letter followed plant’s inspections by the FDA between July and August. It was the third warning in the last 15-month period.

Earlier in September, the FDA issued warning letters to Ranbaxy’s factories in Paonta Sahib in Himachal Pradesh and Dewas in Madhya Pradesh and had blocked the import of 30 generic drugs from these two facilities to the United States.

Ranbaxy said that it would co-operate with the FDA and would remain wholly compliant with the US regulatory standards.

Shares in Ranbaxy shed 1.55 per cent to close at Rs 520.05 on Thursday on the Bombay Stock Exchange.