Who's not congratulating Putin: Russia's middle class

But underscoring a split in Russian society, thousands also came out for a pro-Putin concert.

Tens of thousands of Muscovites took to the streets Monday to protest against an allegedly stage-managed election that ensures Vladimir Putin another six years as Russia's president. But several thousand people came out for an upbeat rock-concert-cum-rally under the Kremlin wall to support Mr. Putin's return to supreme power.

The mood at both meetings was cheerful, and none of the feared violence materialized. However, about 100 people were arrested at an another, unsanctioned, anti-Putin demonstration in Lubyanka Square, a sign that Russian police are ready to crack down on anyone who strays from the strict rules for public assembly laid down by authorities.

About 100 protesters were also arrested in St. Petersburg, where about 2,000 gathered for an unauthorized rally, Russian news agencies reported.

An estimated 20,000 people attending a permitted anti-Putin rally on Pushkin Square, chanted "Russia without Putin" and "Putin is a thief," and many displayed the original hand-drawn posters that have become a hallmark of this protest movement. One read: "We want to elect our president, not be given a lifetime leader!"; another said: "Moscow doesn't believe in tears," a combined reference to a beloved Soviet-era movie and widely-shown news clips of Putin apparently crying at his victory celebration Sunday night.

The rally was addressed by several leaders of the protest movement that's burgeoned since allegedly fraud-tainted Duma elections in December

They included anticorruption blogger Alexei Navalny, who toned down his earlier calls for an "Occupy the Kremlin" tent city, and merely warned the Kremlin to take heed that "there are millions of Russians, many from big cities, who do not recognize the legitimacy of these election results."

Sociologists have been pointing to a split in Russian society for some time, between Russia's conservative and working-class hinterland and the rising middle class, which tends to be professional, educated, and business-oriented, that's concentrated in cities like Moscow and St. Petersburg.

Sunday's voting bore this out, with Putin winning handily in most of the country, but garnering just 48 percent of the votes in Moscow. One of the country's lowest voter turnouts, just 49 percent, was also recorded in Moscow.

Whether Putin is able to come to terms with this assertive -- yet indispensable -- new minority may yet come to define the success or failure of his fresh term in the presidency.

"These were elections without any real alternative," says Yelena Melkumyan, a teacher of international relations. "People who supported Putin did so out of habit. It's difficult to change stereotypes. That's why it's so important to protest. The new generation understands that something has to be done to change the system, to put forward new leaders, to struggle against all the shortcomings we see around us. Putin is not capable of doing this."

Mikhail Prokhorov, the billionaire owner of the New Jersey Nets basketball team who won just 8 percent of the votes, addressed the crowd and pledged to start a new political party that would speak on behalf of Russia's new middle class.

The rally broke up peacefully, with a few hundred hard core protesters following leftist leader Sergei Udaltsov in staging a sit-in on Pushkin Square.

"If it was a free election, why have they flooded the entire city with troops?" shouted Mr. Udaltsov. "I'm not leaving here today, not until Putin comes for me."