Russia's media regulator has blocked the online anonymity service Tor in what is seen as the latest move by Moscow to bring the Internet in Russia under its control.
Roskomnadzor announced it had blocked access to the popular service on December 8, cutting off users' ability to thwart government surveillance by cloaking IP addresses.
"The grounds were the spreading of information on the site ensuring the work of services that provide access to illegal content," Roskomnadzor told AFP in explaining the decision.
In recent months, Russia has accused social-media platforms and other tech giants of flouting the country's Internet laws by not removing content banned in Russia. The authorities have also sought to force foreign firms to open representative offices and store data collected on Russian citizens inside the country.
Russian courts have ordered Google to pay fines totaling hundreds of thousands of dollars for failing to delete banned content on its search engine and on YouTube, and have fined Facebook, Twitter, WhatsApp, Telegram, and TikTok on similar grounds.
Aside from Tor, Russia has blocked six other virtual private network (VPN) service providers that shield IP addresses, and still seeks to block others.
The moves threaten to cut off the main avenue for the country's political opposition, rights groups, and activists to express their views.
Critics accuse the authorities of trying to quell dissent.
Russia launched a "sovereign Internet" project in 2019 that could allow the Russian segment of the Internet, or RuNet, to separate itself from the World Wide Web.