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 the Ekho Moskvy radio that Udaltsov and 13 other protesters were detained.
Several dozen protesters held a similar rally in St. Petersburg. Police did not detain anyone.
Popular support for opposition groups is minimal in Russia. Their activities have been thwarted as authorities ban their rallies and police regularly break up their gatherings.
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.