Russians across the country gathered in force to protest recent parliamentary elections results.
But not all the protests against the win by the United Russia Party were peaceful.
In St. Petersburg, several demonstrators were arrested by security forces.
Dozens were also taken into custody in eastern Russia.
The protests are being led by Boris Nemtsov, leader of Russia's opposition, and a staunch critic of Vladimir Putin's ruling party.
At a rally in Moscow, he called for the release of supporters, the annulment of the elections as well as resignations of several top officials.
(SOUNDBITE) (Russian) OPPOSITION LEADER BORIS NEMTSOV
"I expect a big rally, I hope it will be peaceful and will have friendly atmosphere, I expect a resolution to be adopted at this rally, we propose five demands in the resolution: we suggest and we demand the immediate release all political prisoners, we have over 50 comrades arrested after the Chistye Prudy rally on December 5, they are in prisons. We also demand to cancel the false election in which 13 million votes have been stolen from us. "
Demonstrators say they want an end to the wide-spread corruption and nepotism they claim is common among United Russia party members.
(SOUNDBITE) (Russian) NIKOLAI, PROTESTER, SAYING:
"(I came) to show that there are a lot of people who disagree, that people have seen falsifications and they are not prepared to accept it. I went to the elections, to vote and I came here to also give my vote."
Putin's party narrowly won a majority in the latest polls, the worst electoral result since he came to power in 1999.
That has given Nemtsov a boost in popularity with prominent journalists and celebrities pledging their support for a new Russia without Vladimir Putin.
Jessica Gray, Reuters