Moscow police detained almost 700 protesters Saturday as thousands gathered downtown in continuing protests that had been building for weeks after election officials prevented opposition candidates from running in September local elections.
OVD-Info, a monitoring group, said police had detained at least 317 people before or at Saturday's protest, which was attended by thousands of people.
Along with the arrests of the mostly young demonstrators, several opposition activists who wanted to run for the council were arrested throughout the city before the protest.
"About 3,500 people are attending the uncoordinated event in the centre of Moscow, of which about 700 journalists and bloggers informed earlier about their participation in covering the rally", the police officer noted.
But after some 22,500 people turned out for a protest in central Moscow last weekend that was approved by city officials - the largest showing at an opposition-led rally in recent years - the authorities decided that enough was enough. "They are behaving in a way that is nearly sadistic", Yashin said on Twitter, announcing another Moscow protest for August 3. He continued to demand that Sobol and other opposition leaders to be placed on the local ballots.
On Friday Navalny allies said police had also searched their campaign headquarters in the latest raids.
After several hours, police cleared the area, but many protesters went to a square about a kilometer (half-mile) away and detentions began again.
Police wrestled with protesters around the mayor's office, sometimes charging into the crowd with their batons raised.
The move touched off unusual anger among Russian liberal society, who see it as a sign that the Kremlin under president Vladimir Putin will now not tolerate even low-level, legal political opposition.
Alexei Navalny, Russia's most outspoken opposition figure, was among those detained during the week, and was later sentenced to 30 days in prison for allegedly violating the country's protest laws by calling for the demonstrations Saturday.
A Russian organization that monitors political arrests says more than 500 people have been detained in Moscow during a demonstration protesting the exclusion of some opposition candidates from the September 8 ballot for the Moscow city council. He had previously claimed that the country's future was at stake due to the barring of opposition candidates from running.
Raids were also carried out, as police forced their way into Navalny's video studio as the studio was conducting a live webcast about the election protest.
"The searches against independent candidates for Moscow's city parliament mean that legal politics has finished in Russian Federation".
The 45-seat Moscow City Duma is controlled by the pro-Kremlin United Russia party.
Kremlin critic Mr Navalny was jailed for 30 days on Wednesday and other members of the opposition have had their homes searched.