Opposition activist and an organizer of the Day of Wrath rally in Moscow, Sergei Udaltsov, will remain in custody until Monday, a police spokesperson said.
Udaltsov, who heads the Left Front opposition movement, was detained among 13 other protesters at an unsanctioned rally in downtown Moscow on Saturday.
"Udaltsov will be detained until Monday over disobedience to police," the spokesperson said.
The other activists have been released, the spokesperson said.
The protesters attempted to stage an unsanctioned protest in front of the Russian president's administration and were detained by police.
Earlier on Saturday, the activists attended the Day of Wrath rally at the monument to Karl Marx on Teatralnaya Square.
The event was authorized for the first time by the Mayor's Office and gathered some 300 opposition activists.
Requests to authorize the Day of Wrath rallies were invariably turned down by the Moscow authorities in the past, while unauthorized protests were dispersed by police.
MOSCOW, February 12 (RIA Novosti)