New Delhi : Drug firm Wockhardt said the US health regulator has issued a warning letter to its step down subsidiary Morton Grove Pharmaceuticals Inc.

"The United States Food and Drug Administration (USFDA) has issued a warning letter to Morton Grove Pharmaceuticals Inc, USA, a stepdown Subsidiary of the company," Wockhardt said in a filing to BSE.

The company, however, did not provide any details about the reasons for the issuance of warning letter and when it was issued.

"This would mean that current portfolio of the company will continue to be made available in the market. However, new approvals will be withheld till resolution," it added.

The company, with the help of the consultants, has already initiated appropriate measures since last several months to address the issues raised by USFDA," Wockhardt said.

Shares of Wockhardt closed at Rs 751.10 per scrip on BSE, down 0.05 per cent from previous close.