Roskomnadzor, Russia's telecommunications watchdog, has filed today a lawsuit against instant messaging app Telegram, asking a Moscow court to rule in favor of restricting access to the service inside Russia's borders.

Today's Roskomnadzor lawsuit is related to years-long of legal battles between Telegram and Russian authorities.

Russia's Supreme Court orders Telegram to hand over keys

All stems from the fact that FSB, Russia's main intelligence service, had previously requested access to Telegram encryption keys so it could access encrypted messages sent through the app.

Telegram refused to help, and FSB had filed a lawsuit to gain access to these encryption keys on the ground of national security and the agency's fight against terrorism.

All court rulings were in favor of the Russian state, with a final decision coming from Russia’s Supreme Court last month, which ruled that Telegram must hand over users' encryption keys to FSB agents without a court order, whenever agents came calling.

Telegram, a London-registered business, responded through its lawyers, saying it has no such plans. Trying to fight Russian pressure, Telegram filed a lawsuit against the Russian government at the European Court of Human Rights (ECHR).

Lawsuit is the first step in the national ban procedure

The lawsuit filed today by Roskomnadzor is the first phase in the legal steps necessary to have a web service banned in Russia. If the Moscow court rules favorably for the communications watchdog, Roskomnadzor will add Telegram's domains to Russia's national blocklist.

Regulations rule that telcos and ISPs must abide by the blocklist and will be forced to ban Telegram across the country.

Telegram founder and CEO Pavel Durov, usually very outspoken on social media, has not commented on today's lawsuit.

Threats to block Telegram unless it gives up private data of its users won't bear fruit. Telegram will stand for freedom and privacy. — Pavel Durov (@durov) March 20, 2018

Telegram is one of Russia's most popular IM client, but it's also popular across the Middle East. The service recently celebrated achieving a new milestone of 200 million active users per month.

UPDATE [April 13, 2018]: Russian authorities have officially banned Telegram, as anticipated.