Pavel Durov, the founder of VKontakte, said he refused the request and posted a statement saying so on his page.
"Our response remains a categorical refusal -- Russian jurisdiction does not extend to Ukrainian users of VKontakte...Giving personal of Ukrainian to Russian authorities would not only be against the law, but also a betrayal of all those millions millions of people in Ukraine who have trusted us."
Earlier this month, Durov resigned as CEO of VKontakte, saying that since December 2013 when Russia requested the information, he has not had any property but still has a "clean conscience and ideals that I am willing to defend."
In an interview just this week, Russian President Vladimir Putin said his government did not engage in mass surveillance or the collection of people's personal data.
Notable deaths of 2014 [PHOTOS]
Kim Jong Un's absence tied to ankle surgery