In a post the same day on Telegram, Russian authorities confirmed that they took measures to partially restrict access to Facebook, in the form of slowing down traffic to the site. The censor accused the company of restricting access to four Russian media outlets.

Alphabet, TikTok and Telegram did not respond to requests for comment.

Tech companies previously have bowed to pressure from Russia’s Internet censor. In September, Apple and Google removed an opposition voting app from their app stores as balloting began in the country’s parliamentary election, after the Russian censorship agency accused the firms of interfering in the country’s political affairs. The agency threatened fines and possible criminal prosecutions.

Internet freedom advocates warned that tech platforms are a critical source of independent information for people in Russia and that limiting access to those platforms may leave people with only state propaganda that is inciting the war with Ukraine.

“Major tech companies have a responsibility to their Ukrainian and Russian users to respect their rights to freedom of expression and access to information, especially in the time of war and political crisis,” said Natalia Krapiva, the tech legal counsel of Access Now, a nonprofit that advocates for Internet freedom.

But she said tech companies still need to take precautions to ensure that their platforms aren’t abused.

“They do, however, also have a responsibility to keep their users safe and identify and respond to any campaigns of disinformation that may result in violence and abuse,” she said.

Cat Zakrzewski is a technology policy reporter, tracking Washington’s efforts to regulate Silicon Valley companies. Her reporting covers antitrust, privacy and the debate over regulating social media companies.