WASHINGTON (Reuters) - A U.S. judge on Thursday granted a preliminary injunction barring the Obama administration from trying to regulate electronic cigarettes and prevent them from being imported into the United States.

In a sharply worded decision, U.S. District Judge Richard Leon scolded the Food and Drug Administration for trying to assert jurisdiction over the cigarettes, which are battery-powered or rechargeable devices that vaporize a liquid nicotine solution.

“This case appears to be yet another example of FDA’s aggressive efforts to regulate recreational tobacco products as drugs or devices,” he said in granting an injunction barring the FDA from regulating the cigarettes as a drug-device combination.

E-cigarettes were first made in China and are sold mostly on the Internet. The battery-powered devices work by a emitting a “puff” or fine mist of nicotine in the lungs.

A law passed last year gave the FDA power over regular cigarettes and other tobacco products. But while e-cigarettes contain nicotine, they do not contain tobacco and are not subject to the new oversight.

But FDA maintains it has control over the products because they aim to treat people suffering from nicotine withdrawal, making them a combination drug and device -- two things the agency has regulated for years.

A company that imports the electronic cigarettes, Smoking Everywhere Inc., had two shipments detained by the agency in late 2008 because they were not FDA approved.

The FDA later barred the importation of electronic cigarettes and their components by three Chinese companies. The FDA also denied entry to more than 35 shipments from 20 other manufacturers, according to the court ruling.

Smoking Everywhere and another manufacturer asked the court to bar the FDA from refusing entry to their products and regulating them, which Leon agreed to do.

PRODUCE NO SMOKE

The court noted that the other company in the case, NJOY, labeled its products with a disclaimer that they were not for smoking cessation. On its website, NJOY says one main reason people use the product is that it produces no smoke and can be used in some places where smoking is prohibited.

Smoking Everywhere said in its original complaint last year that it had imported and sold more than 600,000 electronic cigarette kits.

A lawyer representing the companies said that he expected the FDA to appeal the decision, although he argued the judge anticipated many of the arguments the agency could make.

“It’s going to be difficult for the FDA to get Judge Leon reversed,” said the lawyer, Kip Schwartz of Thompson Hine LLP. “But that won’t stop them.”

FDA spokesman George Strait said the agency was reviewing the judge’s decision, adding that “the public health issues surrounding electronic cigarettes are of serious concern.”

The agency has said it is worried about safety issues and last year warned that some samples it tested contained carcinogens and toxic chemicals. The World Health Organization has also warned against their use, saying there was no evidence to prove they were safe or helped smokers break the habit.

The Campaign for Tobacco-Free Kids and other consumer advocacy groups blasted the ruling, saying it put U.S. consumers at risk.

“This is a misguided and mind-boggling decision by the court,” said National Research Center for Women & Families President Diana Zuckerman. “Nicotine is an addictive drug, and therefore e-cigarettes are a drug delivery system.”

A 2009 Zogby poll found Americans divided over whether the e-cigarettes should be regulated by the government