About 700 people were arrested in Moscow and up to 900 in St. Petersburg in widespread rallies Monday against the Putin government that drew thousands of protesters in more than 100 cities.
"We are canceling the rally on Sakharov Avenue and moving it to Tverskaya Street", a main thoroughfare to the Kremlin, he said. "This is a very powerful idea, and that is why there are so many people". He was arrested at his home in Moscow roughly an hour before it was due to start.
The White House has condemned the arrests of protesters at anti-corruption rallies in Russian Federation.
A White House spokesman said the United States condemned the detentions.
An actor, who takes part in the Russia Day festivities, walks past a police line in Moscow, Russia, Monday, June 12, 2017.
Tens of thousands of protesters held anti-corruption rallies across Russian Federation on Monday in a show of defiance by an opposition that the Kremlin had once dismissed as ineffectual and marginalized. In St Petersburg, dozens were reported detained by police at the protest.
The demonstrators appeared to be mostly young people - those who were born or grew up during Putin's 17 years of leading Russian Federation.
Similar to the March protests, young people predominated in Monday's rally. Putin is expected to seek another term in 2018, and Navalny has already announced his intentions to run.
Alexey Navalny was one of the first people to be detained on Monday - in fact, he posted a picture on Twitter of policemen waiting for him outside his apartment.
Demonstrators in Monday's opposition protests across Russian Federation say they are fed up with endemic corruption among officials.
Police in Russia's Far East have detained several people trying to demonstrate as part of nationwide anticorruption protests organized by opposition politician Aleksei Navalny and his supporters.
As the correspondent of the TV channel Jill Dougherty, the young people with whom she was able to talk, think about your future and about where we could go to the money "stolen by corrupt officials", "on education, bridges and so forth".
Alexei Borsenko, a Vladivostok demonstrator who eluded a police attempt to detain him, cited Iceland's prime minister stepping down in the fallout from the "Panama Papers" scandal, while "our prime minister is caught on such big corruption cases and he doesn't go anywhere".
Pretext for his arrest has been a call to move the rally in Moscow to an unsanctioned location. Navalny himself was arrested on Monday before reaching the march in Moscow.
According to OVD-Info, a nongovernmental organization, nearly 700 people have been arrested in Moscow, and hundreds more in St. Petersburg. On the Field of Mars, after a polite warning to disperse, OMON forces surrounded people chanting, "Russia will be free", and led them to police vans.
As police detained demonstrators, hundreds of others shouted slogans including "Putin is a thief" and "Shame!"
This is a challenging time for opposition youth all across Russian Federation, from Moscow to Siberia to the Northern Caucasus.
A TASS correspondent reported from the courtroom that Navalny has been found guilty of a repeated administrative offense, in particular violating the rules of organizing or holding a rally.
Organizers in over 200 cities had filed requests to hold demonstrations Monday, out of which almost 120 were granted and 50 were rejected.
Authorities allowed the unsanctioned rally to proceed, although riot police cut the crowd in half and began pushing the lines while grabbing some people from the crowd.
A young demonstrator is arrested by riot police during a demonstration in downtown Moscow, the Russian capital.
Navalny said contractors hired to build a stage at the agreed-upon venue couldn't do their work.