MOSCOW, May 24 (RAPSI) - VKontakte, Russia's largest social networking website, was put on the list of websites hosting prohibited content by mistake, Roskomnadzor spokesman Vladimir Pikov told Digit.ru on Friday.

Roskomnadzor (the Federal Service for Supervision in the Sphere of Telecom, Information Technologies and Mass Communications) blacklisted VKontakte earlier this morning.

However, once the regulator recognized the mistake, the site's IP address was removed from the list.

"Roskomnadzor needs to launch an internal investigation to minimize the chances of such violations, including the so-called human factor," Ruslan Gattarov, Chairman of the Federation Council's interim Commission on Information Society Development, said.

VKontakte is the Russian version of Facebook and is one of the country's most visited sites. Established in 2006, VKontakte has around 200 million registered users and is more popular than Facebook in Russia.

The blacklist of websites was approved on November 1, 2012 and is monitored by Roskomnadzor. It primarily includes websites that contain child pornography, and information about how to commit suicide and drug abuse. If a website is found to host such information, it can be closed down without a court order.

If a website contains other types of prohibited information, the decision to close the website can only be made by a court. According to the rules of register keeping, a site's management has three days to delete the prohibited information, otherwise the telecom operators will block access to the website in Russia.

Earlier this month, the Russian edition of Wikipedia made the blacklist with an article related to cannabis smoking. In early April, the article was banned and later excluded from the blacklist after editing, but then reappeared with original wording thus prompting the regulator to block it again.