The FDA today warned five firms which market e-cigarettes citing unproven health claims and poor manufacturing practices. FDA said that their products violate drug safety laws.

E-cigarettes or electronic cigarettes are tobacco-free devices which are shaped like cigarettes, cigars, or pipes. People who use these cigarettes get a hit of vapor containing nicotine or other substances.

These e-cigarettes are sold in shopping malls and through the internet. The FDA says that they are unapproved drug delivery devices which can't be sold legally until proven safe and effective.

However, lat year, the e-cigarette industry filed lawsuits which blocked an FDA ban. The FDA has now issued strict warning letters to five companies that market e-cigarettes. The warnings give the firms 15 working days to correct "practices which violate various provisions of the Federal Food, Drug, and Cosmetic Act."

FDA said at a teleconference, "The companies must demonstrate to the agency that their products are safe and effective for their intended use. Also they must take steps to ensure the quality and purity of the products."