Moscow, Russia - Russian authorities have arrested an American journalist from Radio Free Europe/Radio Liberty for having failed to register as a "foreign agent," according to the US broadcaster.

Alsu Kurmasheva, who also holds Russian citizenship, potentially faces up to five years in prison, the radio station said in a statement late on Wednesday.

The editor has long reported for the broadcaster on ethnic minorities in the Russian republics of Tatarstan and Bashkortostan, it said.

This is her second arrest. Kurmasheva, who lives with her family in Prague, had travelled to Russia in May because of a family emergency.

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Shortly before her return flight on June 2, she was temporarily detained for the first time in the city of Kazan. At the time, she said authorities confiscated her passports and fined her for failing to register her US passport in Russia.

Kurmasheva had been waiting for her passports to be returned when the new charge of failing to register was announced and she was detained again.

Since 2012, Russia has used foreign agent laws against perceived government critics who receive funding from abroad or are deemed to be "under foreign influence," including civil society groups, media outlets, independent journalists, and activists. Those on the register are also subject to increased oversight of their finances.

Russian media reported that Tatarstan investigators believe Kurmasheva gathered material on the conscription of university teachers for military service in order to write an "alternative" analysis that does not correspond to the official Russian position.

She is accused of discrediting Russia and its army in its war against Ukraine, which is a punishable offense in Russia.

The incident threatens to further strain the already extremely tense relationship between Russia and the US. At the beginning of the year, Russia's FSB domestic intelligence service arrested Wall Street Journal correspondent Evan Gershkovich and accused him of espionage, which he denies.