New Delhi - Shares of Ranbaxy Laboratories Ltd, India's largest drugmaker, plunged Wednesday after the United States banned the sale of 30 generic medicines made in two India-based manufacturing units.

The Food and Drug Administration (FDA), the US food and pharmaceutical watchdog, issued an import alert Tuesday that blocked entry of the drugs, including generic versions of the antibiotic Cipro and cholesterol medicine Zocor, citing manufacturing deficiencies.

Ranbaxy, which is in the process of being acquired by Japan's Daiichi Sankyo Co for an estimated 4.3 billion dollars, said it was disappointed by the FDA action.

"The company has just received the warning letters that FDA has issued and has not had the opportunity to review the concerns that FDA has determined as unresolved," a company statement said Wednesday.

Ranbaxy said it looked forward to cooperating with the US regulator to resolve the issues once it had an opportunity to review them.

The US announcement said the sales and import ban do not apply to drugs manufactured in facilities other than the two Indian plants at Paonta Sahib and Dewas. Ranbaxy has three manufacturing units in the United States.

Ranbaxy shares were trading down 6.79 per cent by the afternoon on the Bombay Stock Exchange. (dpa)