Moscow: Vkontakte, Russia`s biggest social networking website, was put on a state registry of blacklisted websites by mistake Friday, an official said.
"This was a mistake. Our employee put a tick in the wrong place," said Vladimir Pikov, spokesman for Russia`s telecom watchdog Roskomnadzor.
"We will remove VKontakte from the registry and it should be accessible for everyone."
Some 40 million people every day use VKontakte, often referred to as "Russia`s Facebook".
A law creating a register of blacklisted websites containing what the authorities deem "harmful content" was approved by the Russian parliament in July 2012.
Under the law, the authorities can block access to sites containing child pornography, drug-related material, extremism and details about how to commit suicide. No court order is needed to block access.
Other sites containing offensive material can be shut down by a court order.
Rights groups condemned the registry, which has been up and running since November, as an attempt to crack down on internet freedom.
Roskomnadzor has in the past temporarily blocked access to Google and YouTube due to "technical errors".