Kremlin critic and opposition leader Alexei Navalny has been handed a 15-day jail sentence for his part in a big anti-government protest in Moscow.
Sunday's protest and others like it across Russia were estimated to be the largest since 2012 and come a year out from a presidential election Vladimir Putin is expected to contest.
Opinion polls suggest Navalny, who hopes to run against Putin, has little chance of unseating the Russian leader, who enjoys high ratings.
But Navalny and his supporters hope to channel public discontent over corruption to get more support.
Navalny, who will appeal the court's verdict, was found guilty of disobeying a police officer at Sunday's Moscow protest and sentenced to 15 days in jail. He was also fined for organising the protest, which authorities say was illegal.
Navalny told reporters in the Moscow courtroom that he and his allies would not give up.
Police detained more than 1,000 protesters across Russia on Sunday as crowds took to the streets, at Navalny's urging, to demonstrate against corruption and demand the resignation of Prime Minister Dmitry Medvedev.
Medvedev's spokeswoman has dismissed corruption allegations against him as "propagandistic attacks".