Moscow has warned Twitter that it must store Russian users' data in Russia under a new law that took effect in September, news organizations reported on November 11.
Russia's Internet regulator, Roskomnadzor, reportedly issued the demand after Twitter recently changed its policies and started collecting and storing Russian users' personal data.
Moscow passed a law last year that requires Internet services that store Russian citizens' personal data to do so using Russia-based servers starting on September 1.
Roskomnadzor has the authority to block and fine sites that do not comply.
Supporters of the move say it will help protect the public's data and strengthen national security, but critics view it as part of the state's tightening of control over the Internet.
The regulator had said in July that the law would not affect Twitter, because the company did not store personal data at the time.
But the regulator told the Financial Times, AFP, and other outlets on November 11 that the situation has now changed.
Twitter declined to comment.