MOSCOW -- Moscow police have detained dozens of protesters and several opposition leaders to disperse an unsanctioned rally in a square outside the headquarters of the Federal Security Service (FSB).
In all, police say about 40 people were detained in Moscow and 26 in St. Petersburg during protests on December 15.
Opposition leaders Sergei Udaltsov, Aleksei Navalny, Ilya Yashin, and Ksenia Sobchak were among those detained. They were released later the same day without charge.
Protesters, gathered in freezing temperatures, were dragged away to police vans by officers in riot helmets for carrying political signs or symbols, such as the opposition white ribbon, or for chanting political slogans against President Vladimir Putin.
Hundreds of police officers surrounded and blocked off the square to prevent more people from approaching the monument to victims of Soviet-era repressions, where many were laying flowers as a sign of protest.
A police helicopter hovered above the crowd all afternoon and police were seen photographing people as they placed flowers on the monument.
"This was an unsanctioned event but people showed up anyway even though few people were expected to show up," said Filip Talanov, 42, a designer who has been participating in protests since Russia's parliamentary elections in December 2011. "We are now seeing a process toward a change of power, which will be gradual, but which is now irreversible."
PHOTO GALLERY: Antigovernment Protest Held In Moscow
There was a heavy police presence ahead of the unsanctioned opposition rally in central Moscow.
Protesters laid flowers on a monument dedicated to victims of political repression near the headquarters of the Federal Security Service (FSB) on Moscow's Lubyanka Square.
Independent sources estimated that the crowd of demonstrators numbered around 2,000 people.
Some protesters carried political signs, or chanted political slogans against President Vladimir Putin.
An elderly participant at the Moscow demonstration
Police made several arrests.
Opposition leader Sergei Udaltsov spoke at the demonstration on Lubyanka Square .
The police later arrested Udaltsov and said they plan to charge him and other opposition leaders with organizing an unsanctioned protest.
A police helicopter loomed over the crowd all afternoon and police were also seen photographing demonstrators.
The demonstration was called to mark the first anniversary of major rallies that were held in the wake of the December 2011 elections, which were won by Putin's ruling United Russia party.
Those elections were widely criticized by international monitors as undemocratic.
Police say about 700 people attended the unsanctioned demonstration in Moscow, while independent sources estimated attendance was about 2,000.
That figure is still far below the tens of thousands who protested a year ago.
Protests Held Elsewhere
In contrast to previous protests, the Moscow authorities did not grant permission for the demonstration.
The move spurred some prominent human rights activists to urge people not to attend, saying the protest was a "trap" the authorities could use to conduct mass arrests.
Many opposition leaders nonetheless encouraged citizens to come to the square.
Police detained opposition leaders Udaltsov, Sobchak, Navalny, and Yashin before they reached the demonstration site.
They were taken to a Moscow police station and held for several hours before being released.
There had been earlier reports that they could have faced serious penalties under a draconian law on demonstrations passed earlier this year.
Besides Moscow and St. Petersburg, similar demonstrations against the government were also conducted on December 15 in Yakaterinburg, Samara, Perm, and other cites.
Opposition leader Boris Nemtsov said the opposition Coordinating Council would meet on December 16 to discuss its next moves.
Nemtsov told RFE/RL's Russian Service that he thinks mass protests remain an important tool for bringing about change in Russia.
"Putin's propaganda said from the very beginning that either no one is coming out to the protests or the protest movement has already dried up," he said. "This is a special form of brainwashing for people who don't participate in the rallies but who sympathize with them.
"Nonetheless, I have to say that 40 percent of Russian citizens support the protest actions and those who participate in them, even if they don't participate themselves. This is a type of propaganda aimed at demoralizing the citizenry, but nothing will come of it. We believe that peaceful acts of mass protest are a very effective and realistic means of changing the political regime."
Nemtsov also told RFE/RL that, in addition to further mass protests, the opposition may participate in upcoming elections for governor of Moscow Oblast and mayor of Moscow.
Marina Shpar, 46, who was holding a white carnation at the Moscow rally, was hopeful that the protest movement would not dissipate after a year in which the authorities have offered few if any concessions to the opposition.
With reporting by Dozhd TV, Interfax, and Reuters