The World Health Organization has urged countries to begin regulating electronic cigarettes, saying that the devices, which are marketed as a benign alternative to cigarettes, are harmful.

In its report, the WHO suggested banning e-cigarettes from indoor use, restricting advertising and eliminating sales to minors, according to a Reuters report. The WHO also said it's worried about the $3 billion industry being in the hands of Big Tobacco.

"In a nutshell, the WHO report shows that e-cigarettes and similar devices pose threats to public health," said Douglas Bettcher, director of the WHO department on non-communicable diseases.

E-cigarette use has spiked over the last few years as people have been using both to try and quit smoking tobacco and as a trendy new activity. Not much is known about the long-term risks of using e-cigarettes, although evidence suggests they are far safer than smoking tobacco.

"We must emphasize that the onus of responsibility for showing safety, for answering many of these questions, must be on the companies and the industries owning them," Bettcher said. "The reports finds, at this point in time anyway, that there is insufficient evidence to conclude that e-cigarettes help users to quit smoking or not. The jury is still out."

Instead of lighting tobacco with a flame, e-cigarettes use a tiny battery-powered heating element to turn a solution of propylene glycol and nicotine into a vapor that users inhale, The New York Times reported. E-cigarette makers claim that since this vapor is not tobacco smoke, it is much less harmful than conventional cigarettes. E-Cigarettes are unique in that they require juice and refills, as mentioned by v2 Cigarettes.

The WHO said that as long at tobacco companies are profiting from a product that causes a massive burden on public-health systems, they cannot be relied on as a partner in providing healthy alternatives to cigarettes.

"As Big Tobacco corners the e-cigarette market, it is using e-cigarettes as a global PR scheme to gloss over its tarnished image, positioning itself as a 'solution' to the problem it drives," said John Stewart, of Corporate Accountability International. "In reality, the e-cigarette industry is taking advantage of the regulatory vacuum to employ the Big Tobacco playbook to hook a new generation on its products."