Hundreds of people have been arrested during an unauthorised demonstration in Moscow about the exclusion of opposition candidates from the city council election ballot.
The OVD-Info group, which tracks political arrests, said that 638 people were detained during the demonstrations, which began near the mayor’s office before police pushed the protesters into side streets.
State-owned news agency TASS quoted a government spokesperson earlier saying “almost 300 participants” were detained.
Moscow city council elections are due to take place on 8 September but a number of candidates from opposition parties have not been allowed to appear on the ballot paper.
The council election has developed into a significant political dispute between the Kremlin and the capital city’s 12.6 million people.
Prominent opposition figure Alexei Navalny had called for the protest and was sentenced to 30 days in jail on Wednesday as a result.
Police also stormed into an online television station called Dozhd, which was broadcasting the protest, and ordered its editor-in-chief Alexandra Perepelova to be questioned.
Images show violent clashes between the police and the protesters, which police estimated at about 3,500 people, including about 700 from the media.
Demonstrators shouted slogans including “Russia will be free!” and “Who are you beating?”
Earlier this year more than 1,200 people were arrested across Russia during protests against Valdimir Putin’s inauguration for a fourth presidential term.
Mr Putin, 65, was re-elected in a landslide victory in March – extending his grip over the world’s largest country until 2024.
He has been in power, either as president or prime minister, since 2000. His victory makes him the longest-lasting leader since Soviet dictator Joseph Stalin, who ruled for nearly 30 years.
On Saturday, officers used batons against protesters who were chanting “Putin is a thief!” and “Russia will be free!”.
Mr Putin’s critics say he is more of a tsar than a democratic leader.
Mr Navalny, who has been repeatedly detained, published a message ahead of the marches saying: “If you think that he is not our tsar, take to the streets of your cities.
“We will force the authorities, made up of swindlers and thieves, to reckon with the millions of citizens who did not vote for Putin.”