Russia’s communications watchdog, Roskomnadzor, could block access to Facebook in the country next year unless the social network complies with its controversial rules on data storage.

In late 2015, a controversial law was enacted in Russia requiring that personal data of all Russian citizens be stored on servers in Russia, including stipulations that foreign or global companies move Russians' personal data to servers within the country.

"The law is mandatory for everyone," Roskomnadzor head Alexander Zharov was quoted as saying by state-run news agency Interfax late last week. "Either we make sure that the law is observed, or the company will stop operations on the territory of the Russian Federation."

So far, Roskomnadzor has applied the law selectively. Last year, it demanded that LinkedIn comply with the law, but the company refused, and access to it was banned. Earlier this year, Twitter said it would move all of its Russian users' personal data to Russian servers by mid-2018.

Now Roskomnadzor has said that it may inspect Facebook to make sure that it also observes the data storage law by next year. "Facebook has a substantial audience in Russia, but it is not a unique service," Zharov said.

Incidentally, the threat against Facebook comes just days after the social network said it would release data on suspicious accounts that allegedly are registered in Russia and were used to place ads for inflammatory and propagandist content during the U.S election last year, to U.S. Congress. Russian authorities have denied any involvement with the ads.

Authorities denied targeting the social network amid the latest news. "We don't have any bias towards Facebook or any other foreign or local service," communications minister Nikolai Nikiforov was quoted as saying by state-run news agency TASS. "If there is a national law in the Russian Federation, it should be mandatorily applied to all online companies."

Meanwhile, Russian experts say that Facebook is likely to eventually comply with the Russian law.

"They will build a server station in Moscow," Alexei Martynov, head of the new states institute, was quoted as saying by Novye izvestia daily. "It's not difficult, it's just extra costs for [Facebook CEO Mark] Zuckerberg. But he can afford it. He'll be obstinate for a while, but then he'll give in."