Oslo, July 26 (IANS): Norway has notified vendors of electronic cigarettes that all pictures and positive reviews of the products must be removed from websites, media reported.

"E-cigarette is a tobacco surrogate and is therefore covered by the ban on advertising," Xinhua quoted Hilde Skyvulstad, a senior official of the Norwegian Directorate of Health, as saying.

Sellers of the products fear that an advertising ban will hurt their business even though many of their products are nicotine-free and do not look like cigarettes, said local business newspaper DN.

E-cigarettes are battery-powered devices that vaporize a liquid solution, creating an aerosol that is inhaled and simulating the feeling of smoking. Using e-cigarettes is also called "vaping".

E-cigarettes don't contain many other cancer-causing chemicals that are found in regular cigarettes, but they usually contain nicotine, the substance responsible for causing addiction to tobacco products.

The benefits and health risks of e-cigarettes are mostly not certain so far, but a recent report from the Norwegian Institute of Public Health suggests e-cigarettes are not without health risks.

While e-cigarettes are less harmful than smoking tobacco, especially with regards to cancer, the health risks of long-term e-cigarette use in the population are unknown, the report said.

The report has only considered e-cigarettes with nicotine since there has been very little research about e-cigarettes without nicotine.