Police detained an opposition leader and a dozen activists during a rally in Moscow on Saturday that drew hundreds of protesters.
Several hundred activists headed by Sergei Udaltsov of the anti-Kremlin Left Front group braved freezing temperatures to rally in central Moscow to protest what they said was the Kremlin's stifling of democracy, as well as corruption and rising prices.
Authorities had limited the rally to a central square, and riot police started detentions after the protesters moved to the presidential administration building chanting "Time to replace the government" and "Enough with rising prices."
Moscow police spokeswoman Yelena Perfilova told Ekho Moskvy radio that Udaltsov and 13 other protesters were detained.
All detainees but Udaltsov were released Sunday, the group's spokeswoman Anastasia Udaltsova said.
The Left Front leader was set to be released Monday, she added.
Udaltsov's lawyer was pushed out of the police precinct for lending his mobile phone to the client, the spokeswoman said.
Several dozen protesters held a similar rally in St. Petersburg. Police did not detain anyone.
The Left Front is a small opposition group allied with liberal democrats and leftist movements that have been denied registration for municipal and parliamentary elections.