A Russian court has ruled that messaging application Telegram must be blocked in the country.
"Even though only a miniscule proportion of Telegrams 200 million or so users would ever dream of doing anything wrong, let alone committing terrorist atrocities, the Russian government has successfully trampled what appears to be a constitutional right to privacy and free speech for its citizens by blocking the app".
The FSB has said it needs such access to guard against security threats such as terrorist attacks.
"Privacy is not for sale, and human rights should not be compromised out of fear or greed", Durov, who left Russian Federation in 2014, said on Telegram after the ruling.
There is speculation the government could be slow to block Telegram for this reason, although the judge ordered an immediate ban, lasting until the company submits to the FSB's demands. The social media app has become increasingly popular with the cryptocurrency community around the world as a means to share information and, in some cases, transact sales. The service could be unstable without a VPN.
Macron's inner circle - now government advisers or ministers - have grown fond of the Telegram app, which they used to plot his rise to power and his presidential election campaign a year ago.
Around 10 activists were arrested after demonstrating outside the FSB headquarters against the move, Maria Alekhina, a member of the Russian protest punk group Pussy Riot, told Ekho Moskvy radio.
Durov said last week that Telegram had "built-in" features so people could continue using the service during the government's ban.
But the company said the way the service was built meant it had no access to customers' encryption keys. The ruling follows months of battles between Telegram and federal telecom watchdog Roskomnadzor.
The informing application is broadly utilized crosswise over Russian Federation and numerous countries in the Middle East, and around whatever is left of the world.