The coordinator of Russian opposition politician Aleksei Navalny's presidential election campaign staff in Kazan, the capital of the Tatarstan region, has been detained.
Elvira Dmitriyeva told RFE/RL by phone that she was taken to a police station on August 23 and informed that she faced charges of violating regulations governing public gatherings.
Dmitriyeva said the case against her was launched after she posted Navalny campaign material on the Internet.
Earlier this year, Dmitriyeva was fined 10,000 rubles ($170) and ordered to perform community service after a court ruled that she took part in an unsanctioned anticorruption rally on March 26.
Dozens of Navalny campaign workers have been detained or questioned in Moscow and other cities in recent weeks.
Navalny is campaigning for the March 2018 presidential election, in which President Vladimir Putin is widely expected to seek and win a fourth term.
Russian election authorities have said that Navalny will be barred from the ballot because of a financial-crimes conviction that he says was engineered by the Kremlin to punish him for his opposition activity and keep him out of electoral politics.
