Russian police have detained opposition activist Sergei Udaltsov and at least 30 other people during an anticapitalism rally in central Moscow.
Udaltsov's lawyer, Violetta Volkova, told Russia news agency Interfax that her client had been detained for violating the rules of organizing or conducting rallies.
Udaltsov's case will be sent to court, Volkova said, adding that "until the court hearing, which is on [September 25], [Udaltsov] will remain in police custody, he was not released."
A source quoted by Russian news agencies said "about 30 people" were detained during the protest, while Aleksandr Averin, a member of the unregistered Other Russia party, told Russian media that more than 50 protesters had been detained.
Writer and nationalist politician Eduard Limonov was also among those detained during the unsanctioned rally on September 23.
Earlier in the day, a Twitter account linked to Udaltsov wrote that the protesters “walked quietly, without placards and slogans. Police officers came and said ‘they were holding an unsanctioned rally.’”
Udaltsov was released from prison on August 8 after serving a 4 1/2 year prison sentence over his role in organizing a May 2012 protest against President Vladimir Putin and his government on Moscow's Bolotnaya Square.
In July 2014, Udaltsov was convicted of organizing "mass disorder" in connection with the protest, which erupted into violence that demonstrators and police blame on each other.
Upon his release, Udaltsov vowed to revive his dormant Levy Front (Left Front) movement and hold new protests.
On September 13, Udaltsov was briefly detained while protesting in front of the State Duma, Russia's lower chamber of parliament.
On that day, Udaltsov and activist Aleksei Vorontsov were staging single-man protests next to the State Duma to demand amnesty for inmates across Russia in connection with the 100th anniversary of the October Revolution that brought Bolsheviks to power in 1917.