His dramatic announcement was the latest episode in an acrimonious wrangle between Durov and a major shareholder in VKontakte.
Durov said this month he had came under pressure from the Russian security services to reveal data on VKontakte users, and that his refusal led to his losing his stake in the company.
"Unfortunately, the country is incompatible with the Internet business at the moment," he said, adding he planned to create a new mobile social network.
With more than 100 million users concentrated in the ex-Soviet Union, VKontakte is Russia's most popular social network, far outstripping Facebook.
Durov, who founded the company after leaving university, wrote on his VKontakte page on Monday evening that he heard he was leaving the company from news reports.
"The shareholders weren't brave enough to say it directly and I find out about my mysterious dismissal from media."
Durov had initially announced his resignation in a message on April 1 that many took for an April Fool's joke. He later posted a message on VKontakte saying he had not been serious.
But VKontakte said Monday that he had not formally retracted his resignation handed in on March 21, and that since a month had passed, he was out of the company.
"Durov made a joke too far," business daily Vedomosti wrote Tuesday.
Durov claimed the company had been effectively taken over by Kremlin allies.
He referred to Alisher Usmanov, Russia's richest man, who partly controls the Mail.ru group, the majority shareholder in VKontakte, and also to the chief executive of Russia's largest oil firm Rosneft, Igor Sechin, seen as one of President Vladimir Putin's closest confidants.
"VKontakte is passing under the total control of Igor Sechin and Alisher Usmanov," Durov wrote.
Durov had previously announced he had sold his stake, effectively giving control of the firm to Mail.ru, which now controls 52 percent.The remaining 48 percent is controlled by investment group United Capital Partners, which Durov has accused of being tied to the security services and gaining the stake through a hostile takeover.