The Food and Drug Administration said yesterday that it plans to regulate smokeless electronic cigarettes as tobacco products like Kent cigarettes and won’t try to regulate them under stricter rules for drug-delivery devices.

The federal agency said in a letter to stakeholders that it intends to propose rule changes to treat e-cigarettes the same as traditional cigarettes and other tobacco products.

The news is considered a victory for makers and distributors of the devices, which continue to gain popularity worldwide.

E-cigarettes are plastic and metal devices that heat a liquid nicotine solution in a disposable cartridge, creating vapor that the “smoker’’ inhales. A tiny light on the tip even glows like a tobacco cigarette.

Users and distributors say e-cigarettes address both the nicotine addiction and the behavioral aspects of smoking — the holding of the cigarette, the puffing, seeing the smoke come out, and the hand motion — without the more than 4,000 chemicals found in cigarettes.

First marketed overseas in 2002, e-cigarettes didn’t become easily available in the United States until late 2006. Now, the industry has grown from the thousands of users in 2006 to several million worldwide, with tens of thousands new e-smokers every week.

No timeline has been set on the proposed rule changes.

The FDA said e-cigarettes could still be regulated as drugs or drug-delivery devices if they are “marketed for therapeutic purposes,’’ — for example, as a stop-smoking aid.

Craig Weiss, president of Sottera Inc., the Arizona-based company involved in the lawsuit that led to the FDA’s decision, said he was “very happy’’ with the agency’s decision.

Jason Healy, president of e-cigarette maker Blu Cigs, also praised the decision. Once the FDA’s rules covering e-cigarettes are in place, he said, they will help in “weeding out the shady companies.’’

Some e-cigarette makers have claimed that the products will help smokers quit using traditional cigarettes, while other manufacturers have tried to steer clear of the issue.

Nearly 46 million Americans smoke cigarettes. About 40 percent try to quit each year, according to the Centers for Disease Control and Prevention. But unlike nicotine patches or gums, e-smokes have operated in a legal gray area.

The FDA lost a court case last year after trying to treat e-cigarettes as drug-delivery devices, rather than tobacco products. A federal appeals court ruled that electronic cigarettes should be regulated as tobacco products rather than as drug-delivery devices, which must satisfy more stringent requirements such as expensive clinical trials to prove they are safe and effective. The FDA had until yesterday to appeal to the Supreme Court.

The agency issued warning letters last year to several makers of e-cigarettes and their components, saying the companies’ health claims and manufacturing practices broke the law.

The FDA has said its tests found that the liquid in some electronic cigarettes contained toxins besides nicotine — which is toxic in large doses — as well as carcinogens that occur naturally in tobacco.