Ranbaxy Laboratories, India's top drug maker by sales, said on Wednesday it was disappointed by the U.S. Food and Drug Administration's move to ban dozens of its generics.

"The company has responded to each concern FDA has raised during the past two years and had thought that progress was being made," the firm said in a statement.

Health officials have banned dozens of drugs made by Ranbaxy Laboratories Ltd after the generic drugmaker failed to fix numerous record-keeping and other operational problems, although the medications themselves are considered safe.

The U.S. Food and Drug Administration would block more than 30 generic drugs from entering the United States following ongoing procedural violations in manufacturing at Ranbaxy's Dewas and Paonta Sahib plants in India. It also will not approve any new drugs made at the plants until the problems are resolved, the FDA said.

The violations concerned the manufacturing process and not the drugs themselves, the agency added, urging patients not to stop taking any medications and to talk to their doctors.

A sampling of products made at the two plants showed no concerns, they added.

"This is a preventive action taken to protect the quality of the drugs used each day by millions of Americans by ensuring that the process used to make the drugs adheres to the FDA standards for quality manufacturing," said Douglas Throckmorton, deputy director for the FDA's Center for Drug Evaluation and research (CDER).

The move is the latest blow against India's leading drugmaker, which is also the subject of a separate criminal probe by the U.S. Justice Department for allegedly bringing adulterated and misbranded medications into the United States.

The import ban affects numerous, widely-used medications, including generic versions of Merck's cholesterol-lowering drug, Zocor, also known as simvastatin, as well as several AIDS medications.

Other affected drugs include the antibiotic ciprofloxacin, diabetes therapy metformin, cholesterol medicine pravastatin, and the over-the-counter version of allergy drug loratadine. One acquired immunodeficiency syndrome (AIDS) drug — ganciclovir — would be exempt from the ban because of an ongoing shortage, the FDA said.

Despite the ban, agency officials said that consumers should not be affected and that drug shortages were unlikely. The FDA earlier warned Ranbaxy in June 2006 and have since been trying to resolve the problems with the company, which still has not cleaned up its process, it said.

"Ultimately, the deficiencies in the process have reached the level where we think an import alert is justified," FDA's Deborah Autor, director of CDER's Office of Compliance, said. In two separate letters to Ranbaxy, FDA officials found numerous instances of lax written records that are supposed to keep track of equipment cleaning, production controls, and product quality.

FDA inspectors, who most recently searched the plants between January and March 2008, also cited problems with factory workers who did not keep some antibiotics properly contained. Two U.S. lawmakers, who are also investigating whether the FDA knowingly allowed Ranbaxy's drugs to be sold, despite manufacturing violations and fraudulent data, questioned why it was taking the agency years to act.

House Energy and Commerce Committee Chairman John Dingell and Bart Stupak, head of the committee's oversight panel, said the agency had not taken "meaningful regulatory action." "We can no longer leave the methods of assuring drug safety up to discretion of this agency," the Michigan Democrats said in a statement. The FDA's Autor said the import ban would be lifted when the company resolved the violations.