Thousands of people took to Moscow's streets for the fourth weekend in a row to demand that city authorities allow opposition-minded candidates to be allowed on the ballot for the Sept. 8 City Duma elections.
Opposition candidate Lyubov Sobol, virtually the only leading opposition figure who hadn't yet been jailed ahead of Saturday's protest, was detained shortly before the protest was set to begin.
Throughout the rest of the day, 1,001 people were detained, according to the OVD-Info police-monitoring site, sometimes violently.
Saturday's unauthorized protest was smaller than one a week earlier, where more than 1,300 had been detained, but underlined the determination of some Kremlin critics — especially younger people — to keep pressing to open up Russia's tightly-choreographed political system.
Here's a look some of at the most famous images from the most recent protest that have been shared across social media:
The image of one man being detained as he was interviewed by a journalist was widespread on Russian social media.
Footage of the occasionally violent detentions has captured international attention.
Despite nearly all of the opposition's main leaders being in jail, thousands still gathered for the protest.
Observers said the police presence was one of the biggest at such a protest in nearly a decade.
Riot police cordoned off swathes of central Moscow to prevent people from organizing, and observers noted that mobile internet access had been shut off in many areas.
Police removed Sobol, who has been on hunger strike since July 13, from a taxi and bundled her into a van minutes before the start of the protest.
The protest route ran along central Moscow's tree-lined Boulevard Ring.
Opposition activists say the authorities have repeatedly refused to allow protests in central Moscow, leaving them with no choice but to go ahead anyway.
“We don’t live in Zimbabwe,” Moscow Mayor Sergei Sobyanin said in an interview on state television before Saturday's protest, accusing the opposition of having “a desire to usurp power illegitimately.”
Many riot police wore balaclavas to avoid being identified by an activist campaign.
Opposition leaders and activists have called on supporters to continue protesting every Saturday until the Sept. 8 elections.