The app's lawyers insist that the FSB order was adopted by an unauthorized body with an abuse of power, which provides an extrajudicial way of obtaining control over communications of an undetermined number of persons. This situation, according to lawyers, "threatens the security of citizens."
The FSB has repeatedly said that it needs Telegram's encryption keys for protection of the society and the state. Thus, as the FSB specified, the messenger was widely used by terrorists for communication.
Founder and CEO of Telegram messenger Pavel Durov explained that the messenger would use built-in methods to bypass the restriction.
After Telegram had refused to provide encryption keys to the Russian authorities to track down terrorists, Roskomnadzor began blocking Telegram in Russia on April 16. The watchdog has blocked a range of IP addresses belonging to Google and Amazon that were used by Telegram.