The charges carry up to five years in prison. (File)
Russia on Thursday formally charged a detained US-Russian journalist with failing to register as a "foreign agent" in a case rights groups have called an "egregious" escalation of Moscow's decade-long campaign against independent media.
Alsu Kurmasheva is the second US reporter to be detained in Russia this year after the arrest of Wall Street Journal reporter Evan Gershkovich on espionage charges in March.
Rights groups say Alsu Kurmasheva's arrest is the first time Russian authorities have pressed criminal charges of this kind against a journalist.
RFE/RL said in a statement that Russia's Investigative Committee had formally charged Alsu Kurmasheva on Thursday, following her arrest in the central city of Kazan last week.
The charges carry up to five years in prison.
Alsu Kurmasheva is currently being held in pre-trial detention until at least December 5.
Alsu Kurmasheva, who lives in Prague with her husband and two children, had both her Russian and United States passports confiscated during a trip to Russia in June.
Authorities initially said she had failed to notify them of her US citizenship and fined her.
She was arrested on the new charges last week while waiting for her passports to be returned.
Under Russia's criminal code, any Russian citizens that engage in what authorities call the "targeted collection" of information that could harm Russia's national security have to register as a "foreign agent".
Critics say the law is so sweepingly broad that it effectively gives Russian law enforcement the power to arrest journalists at will.
The Committee to Protect Journalists called Alsu Kurmasheva's arrest "the most egregious instance to date of the abusive use of Russia's foreign agents' legislation against independent press".
RFE/RL has called for her immediate release.
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