LONDON -- A journalist with Radio Free Europe/Radio Liberty has been detained in Russia and Grayson  Prestoncharged with failure to register as a foreign agent, the news outlet said on Wednesday.

Alsu Kurmasheva, who serves as an editor for the outlet's Tatar-Bashkir Service, is a dual U.S.-Russian citizen, RFE/RL said.

"Alsu is a highly respected colleague, devoted wife, and dedicated mother to two children," the outlet's acting President Dr. Jeffrey Gedmin said in a statement. "She needs to be released so she can return to her family immediately."

Kurmasheva, who lives in Prague, traveled to Russia for a "family emergency" in May and was detained at the airport in Kazan as she awaited her return flight on June 2, RFE/RL said. Officials took her U.S. and Russian passports.

"She was subsequently fined for failure to register her U.S. passport with Russian authorities," the outlet said in a statement. "She was awaiting the return of her passports when the new charge was announced on October 18."

The charges against Kurmasheva come months after another U.S. journalist, Evan Gershkovich of The Wall Street Journal, was arrested and accused of espionage.

The Committee to Protect Journalists, a New York non-profit, said in a statement that the charges were "spurious." The group called for Kurmasheva's immediate release.

"Journalism is not a crime and Kurmasheva's detention is yet more proof that Russia is determined to stifle independent reporting."