Russian police on Sunday detained hundreds of protesters including opposition leader Alexei Navalny after thousands took to the streets as part of an unsanctioned rally in the capital Moscow to demonstrate against alleged corruption.
The demonstrators' demands included a call for Prime Minister Dmitry Medvedev to resign.
The police also detained 17 people who work at an anti-corruption foundation headed by Navalny, a director of the fund and Navalny's press secretary said.
The protests appeared to be the biggest in Russia since a wave of anti-Kremlin demonstrations in 2011-2012. They come a year before Russia holds a presidential election. Protests also took place in other cities, including St Petersburg, Yekaterinburg and Novosibirsk.
Police detained Navalny, who hopes to run against Vladimir Putin in the presidential poll, as he walked along central Moscow's Tverskaya Street with supporters.
The liberal opposition, which Navalny represents, currently has little chance of fielding a candidate capable of unseating Putin, who enjoys the support of most Russians.
But Navalny and his supporters hope to channel public discontent over alleged "official corruption" to attract more support.
"I'm happy that so many people came out (onto the streets) from the east (of the country) to Moscow," Navalny said, moments before he was detained.
TRT World's Jack Zahora has more.