The Russian government agency responsible for censorship on the Internet has accused Facebook and Twitter of failing to comply with a law requiring all servers that store personal data to be located in Russia.

Roskomnadzor, the Russian censorship agency, "said the social-media networks hadn't submitted any formal and specific plans or submitted an acceptable explanation of when they would meet the country's requirements that all servers used to store Russians' personal data be located in Russia," The Wall Street Journal reported today.

Roskomnadzor said it sent letters to Facebook and Twitter on December 17, giving them 30 days to provide "a legally valid response."

With the 30 days having passed, the agency said that "Today, Roskomnadzor begins administrative proceedings against both companies."

Law allows fines or blocking websites

The law requiring local storage reportedly went into effect in September 2015. But Russia has had trouble enforcing it.

"At the moment, the only tools Russia has to enforce its data rules are fines that typically only come to a few thousand dollars or blocking the offending online services, which is an option fraught with technical difficulties," a Reuters article said today.

Roskomnadzor is apparently threatening fines rather than outright blocking, at least for now. The Journal wrote:

Vadim Ampelonsky, a spokesman for Roskomnadzor, told the television channel Russia 24 that Facebook and Twitter could be fined for not providing information to the watchdog. "We expect to hold them administratively liable," Mr. Ampelonsky said.

Russia previously threatened to block Facebook over its non-compliance with the data-storage law in both 2017 and 2018.

We contacted Facebook and Twitter today and will update this story if we get any responses. UPDATE: Facebook told Ars that it "is in touch with relevant Russian governmental bodies regarding its activities in Russia."

In April 2018, Roskomnadzor moved to block Telegram, an encrypted messaging service.

"The censorship began with Roskomnadzor instructing Internet service providers to block requests to Internet Protocol addresses of Telegram's servers," we wrote at the time.

Telegram users evaded the blocking by using virtual private networks and proxy services. To counter that, Russia reportedly expanded its block list and ended up blocking more than just Telegram.

"But as users flocked to virtual private networks and proxy services to reach Telegram from their mobile devices and computers—or resorted to building their own—government censors added large swaths of IP addresses to the block list," we wrote at the time. "And according to multiple sources within Russia, ISPs there are now blocking large chunks of IP addresses associated with cloud services from Amazon and Google."

Russia started testing "more precise technology to block individual online services" after the attempt to block Telegram failed, "but Moscow has yet to find a way to shut it down without hitting other traffic," Reuters reported in August 2018. Russia had also blocked LinkedIn beginning in 2016, with limited success.