By Maggie Fox, NBC News

(NBC News) - The U.S. Food and Drug Administration proposed asserting its authority over new tobacco products on Thursday, including e-cigarettes, flavored cigars and nicotine gels.

It’s a basic first step, extending the FDA’s regulatory power, but the rule would immediately make e-cigarettes off-limits to kids under 18 and would require makers to tell the agency what’s in their products.

“They would have to report to us the constituents of their products and also how they are making them,” said FDA commissioner Dr. Margaret Hamburg.

But the agency does not propose, for now, limiting Internet sales or television advertising, something that disappoints health experts who fear the new cigarettes make smoking attractive and are hooking a whole new generation.

The American Cancer Society's Cancer Action Network said it was pleased the FDA was doing something.

"However, without swift action from the administration to finalize the rule and take the necessary regulatory steps, many manufacturers of these products can continue to engage in practices, such as advertising and use of flavors, which make them attractive and accessible to youth," the group's CEO Dr. John Seffrin said.

"It should not take several more years for the FDA to be able to specify how it intends to regulate the unfettered marketing of many dangerous tobacco products."

Congress gave FDA the authority to regulate tobacco products in 2009, but the law didn’t include e-cigarettes and certain other products. The legislation also does not allow FDA to ban tobacco products outright, but it can limit sales and marketing and require warning labels.

Public health experts have been clamoring for FDA to extend its authority as e-cigarettes have exploded in popularity.

“It’s like the wild, wild West,” Hamburg said. “Companies can do whatever they want and they can market however they want.”

Use of e-cigarettes, called “vaping”, has taken off in a big way, with sales hitting an estimated $2 billion in 2013. An e-cigarette product ranges from $10 to $120, depending on how many charges it provides.

The little metal or plastic tubes that look like cigarettes have been around in some form since 1963, but only became popular within the past decade. Now more than 250 brands have proliferated.

The new regulations would extend limits that are currently on cigarettes to other tobacco products, including e-cigarettes. That means makers will have to register with FDA and disclose what is in them.

“We expect that the industry won’t be delighted,” Hamburg said.

E-cigarette enthusiasts say vaping is far safer than smoking cigarettes, and some experts say that may well be the case. Cigarettes and other tobacco products contain hundreds, if not thousand of chemicals, and companies were known to add chemicals to enhance flavor and to make the products more addictive.

Supporters and some researchers say they may be useful in helping people quit smoking what they call combustible cigarettes, but the research is limited. Hamburg says it's important to find out just how people really are using them — whether as an aid to kicking the habit or as a crutch to get them past no-smoking zones.

And most health advocates are suspicious of the motives of e-cigarette makers.

"The tobacco industry are very vigorously looking at alternative products to smoking tobacco and are betting a lot that this will be a product for them that will be viable in the future," said American Heart Association president Dr. Mariell jessup.

"It’s being marketed a lot that the smoke is harmless and we don’t know that. We shouldn't be fooled by the promises that these devices, these nicotine delivery systems, are safe."

Jessup is disappointed the new rules don't limit advertising and flavors.

“We will be very disappointed if the regulations don’t address the marketing of these products. In particular, e-cigarettes have been intensively advertised and really focused on youth,” she added.

E-cigarettes contain at the least nicotine and compounds such as propylene glycol, as well as water, to make a flavored mist that looks like smoke and that users can inhale like they would a cigarette.

But Hamburg says no one really knows what else is in them or what the effects are of inhaling the heated-up mixture. “We don’t know as much about the safety and risks of e-cigarettes and that is why we want to be able to regulate them,” Hamburg told NBC News.

“The current situation is of great concern to us,’ she added. “It is an unregulated environment with respect to these products.”

Flavors such as strawberry and “thin mint” make it clear the products are being aimed at children, teens and young adults, Hamburg said.

“They are an easy way for kids to take up a nicotine habit and then go on to cigarettes and other tobacco products that we know carry very serious risks,” she said.

Thursday’s proposals are just the start of a cumbersome process. FDA will publish the suggested regulations and then the public and industry may weigh in. FDA must consider the comments before it enacts a final rule — something that can take months or even years.

“We want to move as quickly as we can but it is a process and it will take time,” Hamburg said. “We think the fact that we are beginning the process is important.”

Advocates are not happy about this.

“I do feel impatient because you cannot watch television or listen to the radio without hearing about these e-cigarettes," Jessup told NBC News. “This is a full-court press from the tobacco industry. They used to be available only in small kiosks in malls and now they are available on the internet. They are ubiquitous now. All of these legislative things move very slowly but the marketing of these products is now moving slowly.”

The FDA banned fruit- and candy-flavored cigarettes soon after the agency was given regulatory power over tobacco in 2009. Hamburg noted that tobacco companies then started making flavored cigars and she said that worries her.

Last year, the FDA found that menthol cigarettes were more dangerous than non-flavored cigarettes, but did nothing to limit their sale.

NBC's Tom Costello and Jay Blackman contributed to this report