Russia’s telecommunications watchdog Roskomnadzor has restricted access to the Signal encrypted messaging service for what it describes as violations of Russian anti-terrorism and anti-extremism legislation.

“User access to the messenger Signal is restricted due to violations of the requirements of the Russian legislation whose fulfillment is necessary to prevent the use of the messenger for terrorist and extremist purposes,” Roskomnadzor told Interfax today.

The statement comes after many Russian users reported experiencing problems using Signal on Friday, and IT experts said the service has been blocked in Russia.

Signal confirmed that some countries block its services and advised users to enable the built-in censorship circumvention feature from Signal Settings > Privacy > Advanced > Censorship circumvention.

“We have already started working on more advanced censorship circumvention techniques, but in order for these efforts to be most effective we need the big companies who are dragging their feet on moving away from plaintext SNI headers to start taking this problem more seriously,” Signal said.

“Solutions like Encrypted Client Hello (ECH) remove the plaintext server name from the TLS handshake, which makes it far more difficult for hostile ISPs to block access to the sites and services you care about — but this isn’t widely supported yet. We hope that starts to change.”

​This follows a March 2023 ban on using many foreign private messaging applications in Russian government and state agencies.

The list of banned messenger apps included Discord, Microsoft Team, Telegram, Threema, Viber, WhatsApp, and WeChat, but Signal was not mentioned.

Russia has also banned the most trustworthy VPN products in three waves: one in January 2020, one in June 2021, and a more recent one in December 2021.

Last month, Apple also removed 25 virtual private network (VPN) apps (including NordVPN, Proton VPN, Red Shield VPN, Planet VPN, Hidemy.Name VPN, Le VPN, and PIA VPN) from the Russian App Store at the request of Roskomnadzor because they were used to access content tagged as illegal in the country.

On Thursday, the Russian government also blocked access to YouTube even though a full block was expected in September.

A Signal spokesperson was not immediately available for comment when contacted by BleepingComputer today.