Russia said on Friday it was partially limiting access to Meta Platforms' Facebook, accusing it of "censoring" Russian media, the latest in a series of steps taken against US social media companies and announced a day after Russian troops crossed the border into Ukraine.
Moscow has been trying to exert tighter control over the internet and big tech for years, something critics say threatens individual and corporate freedom, and is part of a wider crackdown against outspoken opponents of the Kremlin.
The state communications regulator said Facebook had ignored its demands to lift restrictions on four Russian media outlets on its platform - RIA news agency, the Defence Ministry's Zvezda TV, and websites gazeta.ru and lenta.ru.
Meta's head of global affairs, Nick Clegg, said in a statement on Twitter: "Yesterday, Russian authorities ordered us to stop the independent fact-checking and labeling of content posted to Facebook by four Russian state-owned media organizations.
"As a result, they have announced they will be restricting the use of our services."
Meta has been under increasing pressure to combat misinformation on its platforms.
Rohingya refugees from Myanmar are suing Meta over allegations that the social media company failed to act against anti-Rohingya hate speech that contributed to violence against them.
And it has been accused of being instrumental in allowing for the organisation of the January 6 US Capitol riot.
But Meta partners with third-party fact-checkers, including Reuters, which rate and label content for veracity and that content rated false, altered or partly false is shown to fewer users.
Mr Clegg said "ordinary Russians" were using Meta’s apps to "express themselves and organise for action" and that the company wanted them to continue to do so.
Moscow has also increased pressure on domestic media, threatening to block reports that contain what it describes as "false information" regarding its military operation in Ukraine, where Russian missiles have been pounding Kiev as families cowered in shelters.
It was not immediately clear what Russia's restrictions on Facebook would involve.
Last year, Moscow slowed down the speed of Twitter in a punitive move.
"In accordance with the decision of the General Prosecutor's Office, starting from February 25, partial access restrictions are being imposed by Roskomnadzor on the Facebook social network," the regulator, Roskomnadzor, said in a statement.
Meta has already irked Russia's authorities. Moscow routinely fines the company small sums for what it says is a failure to delete illegal content quickly enough.
In December, it issued a much bigger fine of 2 billion roubles ($24.27 million) for what it described as a repeated failure to delete content.
Reuters contributed to this report