Hundreds of opposition supporters have gathered in Moscow to demand that authorities release activists arrested as part of a probe into clashes on the eve of President Vladimir Putin's inauguration for a third term in May.
Some chanted "Russia without Putin." Some banners read, "They are behind bars so that you live in fear."
Investigators said earlier on July 26 they had detained two more activists in connection with the May 6 protests, which erupted into street clashes between police and demonstrators.
Those detentions came on top of 14 activists already under investigation, including 12 in custody.
Opposition leaders told the rally on a central Moscow square that authorities were seeking to intimidate society into silence.
Left Front leader Sergei Udaltsov said "no compromise is possible after these arrests."
"The situation is really clear. They declared a war against the whole civil society. They put pressure on us and imprison us. They do not want a dialogue," Udaltsov said.
"Therefore when war is declared, we either surrender or resist. We employ methods of peaceful resistance such as mass protests, strikes, boycotts of their horrendous laws. That's what we should be talking about today."
Rights activist Yury Dzhibladze said Russia was increasingly looking like neighboring Belarus, whose government has been targeted by Western sanctions due to crackdowns against the opposition.
The sanctioned rally took place amid tightened security measures, with police setting up metal detectors at the entrance to the demonstration site.
Police said one person was detained after he was found to be carrying a knife and several flares.
Police said some 500 took part in the rally, while opposition websites put the figure at 3,000.
Based on reporting by AP, RIA Novosti, and RFE/RL's Russian Service