Russian police forcibly detained nearly 700 people, including prominent activist Lyubov Sobol, attending a protest in Moscow to demand free elections.
Protesters once again took to the streets of the Russian capital on Saturday to decry the exclusion of some independent and opposition candidates for upcoming city council elections.
Riot police were out in full force and at least 685 people have been taken into custody so far, according to monitoring group OVD-info.
In some cases, officers beat them with truncheons as they lay on the floor, the group said.
Ms Sobol, who is on hunger strike, had called on people to attend the demonstration.
She was detained in a taxi as she tried to make her way to the protest and driven off in a police van.
Despite repeated warnings that police would take active measures against demonstrations on Saturday, protesters planned to hold a peaceful walk along the Boulevard Ring that circles central Moscow and is a popular area for strollers.
Helmeted riot police lined the route and seized demonstrators from a scattered crowd on Pushkin Square, pushing them back from another square further along the route.
Police said they had detained 600 people and said 1,500 people had attended the protest, though footage of the demonstrations from different parts of Moscow suggested many more had taken part.
Russian TV channel Doghd said that many of those detained were not provoking police, holding banners or chanting.
Ms Sobol recorded an audio message for her supporters after her detention, saying she was kept in the police cruiser for more than three hours by 12 police officers. She said she still was not told why she was detained.
“I want to express my respect and gratitude to the brave people who took to Moscow streets today,” Ms Sobol said. “To the people who were not afraid… and continue to demand their rights for political representation.”
Last Saturday, nearly 1,400 protesters were detained in Moscow during a similar protest in one of the biggest crackdowns in recent years.
Thousands of people demonstrated, accusing the government of deliberately not registering opposition and independent candidates in the local Moscow election.
As the crowds chanted “Russia without Putin”, police clad in riot gear beat back protesters with batons and roughly detained people.
Russian opposition leader Alexei Navalny, a fervent critic of President Vladimir Putin and ruling United Russia party, was jailed for 30 days after calling for unauthorised demonstrations in Moscow last week.
His supporters have since alleged he may have been poisoned while in custody after suffering an acute allergic reaction.