LOURDES GARCIA-NAVARRO, HOST:

Thousands of Russians have taken to the streets of Moscow and other cities in the biggest anti-government protests in years. The demonstrators were demanding the resignation of the country's prime minister, Dmitry Medvedev. Moscow Police reportedly arrested hundreds of demonstrators, including the organizer, anti-corruption activist Alexei Navalny. Reporter Charles Maynes has been out on the streets of the Russian capital today and he joins us now on the line.

Charles, describe the scene when you were out there. How many people turned up? What did it look like?

CHARLES MAYNES: Well, there were thousands of people. Essentially, this is - Alexei Navalny, the Russian opposition leader, had called for Russians to come out to the central street of Moscow - this is Tverskaya Ulitsa, Tverskaya Street - and essentially just walk down the street towards the Kremlin and circle back. And so in a way you had, you know, the thousands of people there. And it was, in some ways, difficult to know who was a protester and who was just out enjoying a very nice spring day here in Moscow.

GARCIA-NAVARRO: Were there were protests in other cities as well? And this is unusual, right?

MAYNES: This was. Mr. Navalny had called for protests across Russia. We saw 2,000, I think, turn up in - the reports were of 2,000 turning up in Novosibirsk in Siberia. We had 10,000 in St. Petersburg. The estimates here in Moscow are about 20,000. And of course, we saw arrests across the country as well. Moscow, the latest update was over 500 arrests.

GARCIA-NAVARRO: Why were the protesters demanding that the prime minister resign? It's the president, Vladimir Putin, who holds the real power in Russia.

MAYNES: Well, that's right. And Navalny has been a fierce critic of Vladimir Putin. But in this case, he - Mr. Navalny runs an anti-corruption foundation. And he recently published, earlier this month, a - essentially an investigation that he'd done that alleged mass corruption charges against the prime minister, Dmitry Medvedev. It was quite spectacular in some of the findings.

It was said that Mr. Medvedev used charities and NGOs to collect donations from tycoons and state banks and used all these funds to buy all these expensive assets, things like yachts, a vineyard, luxury mansions. And it even included a separate house on one estate for a collection of pet ducks. So it was a colorful report, and it's taken off online. It says something like 13 million views at last time I checked. And clearly, it resonated with the public.

GARCIA-NAVARRO: Is that what emboldened the public to come out? I mean, we've seen harsh crackdowns in the past. It's been several years since large protests have taken place. Why are people ready to risk arrest?

MAYNES: Just talking to people on the streets today - I spoke with one woman who's a doctor who had also already been fined, frankly, from protesting earlier. She said she was fined $300 and, you know, was appealing that to the European Court of Human Rights. So, you know, it's hard to say. But you certainly saw this sense of civil disobedience in the streets today. People were applauding as people were being hauled off by security services.

GARCIA-NAVARRO: Just briefly - what do you think the fallout of this will be? Alexei Navalny has been arrested. Other people have been arrested.

MAYNES: Well - so yeah, we have had 500 arrests so far, and Mr. Navalny's in jail at this point. But it's also important to note that he's a presidential candidate. Alexei Navalny has said that he wants to run for the presidency in 2018 when Mr. Putin's current term ends. It's expected that Mr. Putin will also run for a fourth term. And essentially, you have this kind of game going on where I think Mr. Navalny is using these corruption issues to try and expand his base. And what was really interesting today was just to see how many young people are out on the streets. Certainly, it seemed to me that his message, because he really is an internet candidate - he's basically barred from state television here - and clearly his message is getting across to a younger crowd.

GARCIA-NAVARRO: Reporter Charles Maynes in Moscow, thank you very much.

MAYNES: Thank you. Transcript provided by NPR, Copyright NPR.