Police officers block opposition protesters after the massive rally in Pushkin Square protest in downtown Moscow, Russia, Monday, March 5, 2012. Riot police on Monday broke up an opposition protest contesting Prime Minister Vladimir Putin's victory in Russia's presidential election, arresting dozens of participants, including prominent opposition leaders. The police action followed a rally in Moscow that drew about 20,000 protesters angry over a campaign slanted in Putin's favor and reports of widespread violations in Sunday's ballot. (AP Photo/Ivan Sekretarev)

Opposition protesters gather at a rally in Moscow, Russia, Monday, March 5, 2012. Riot police on Monday broke up an opposition protest contesting Prime Minister Vladimir Putin's victory in Russia's presidential election, arresting dozens of participants, including prominent opposition leaders. The police action followed a rally in downtown Moscow that drew about 20,000 protesters angry over a campaign slanted in Putin's favor and reports of widespread violations in Sunday's ballot. (AP Photo/Misha Japaridze)

Opposition leader Alexey Navalny speaks to his supporters after being released from police custody after the massive rally at Pushkin Square protest in Moscow, Russia, Monday, March 5, 2012. Riot police on Monday broke up an opposition protest contesting Prime Minister Vladimir Putin's victory in Russia's presidential election, arresting dozens of participants, including prominent opposition leaders. The police action followed a rally in downtown Moscow that drew about 20,000 protesters angry over a campaign slanted in Putin's favor and reports of widespread violations in Sunday's ballot. (AP Photo/Sergey Ponomarev)