More than 1000 people have been detained in Moscow as crowds protest a decision to bar some opposition candidates from running for the city council.
More than 1000 people have been rounded up by police in Moscow in one of the biggest crackdowns of recent times against an increasingly defiant opposition.
The detentions came around a protest calling for opposition members to be allowed to run in a local election.
Authorities had declared the protest illegal and sought to block participation, but several thousand people turned up anyway in one of the longest and most determined demonstrations of recent years.
Chants of "Russia without Putin" and "Putin resign" echoed through central Moscow as guardsmen clad in riot gear beat back protesters with batons and roughly detained people on Saturday.
At least one woman and a man appeared to have suffered serious head wounds.
Jailed opposition leader Alexei Navalny had called the protest to persuade officials to allow opposition-minded candidates to run in an 8 September vote.
Authorities say they were barred because they failed to collect sufficient genuine signatures in their support.
The opposition has no seats in parliament and is starved of air time on state TV, where many Russians still get their news.
Burnishing his man of action image, Putin spent Saturday diving to the bottom of the Gulf of Finland in a mini-submarine to honour a Soviet submarine that sunk there in World War II.
Independent monitoring group OVD-Info said police detained at least 1067 people before or at Saturday's protest.
As in past sweeps, many were only held for a matter of hours.
Police put participation at more than 3500 people, of whom it said around 700 people were journalists and bloggers.
Some activists were arrested twice after being released and then returning to protest in a different place.
Reuters witnesses said some of those detained appeared to be ordinary passersby in the wrong place at the wrong time.