Up to 20,000 Russian opposition supporters have gathered for a protest, venting anger against the Kremlin and demanding the release of political prisoners.
Exactly a year ago, a protest on the same square the day before president Vladimir Putin's third presidential inauguration ended in violent clashes between demonstrators and police.
Participants in Monday's rally, which went peacefully amid heavy police cordons, urged the authorities to free more than two dozen people facing criminal charges over their involvement in the protest a year ago.
Since Mr Putin returned to the presidency, authorities have initiated criminal proceedings against opposition activists and the Kremlin-controlled parliament has quickly approved a series of repressive bills that sharply hiked fines for participation in unauthorised rallies and imposed new tough restrictions on civil society activists.
Alexei Navalny, an opposition leader who is facing a trial on embezzlement charges he said were fabricated on Mr Putin's orders, urged the demonstrators today to "throw (Mr Putin) out of the Kremlin".
He ended his speech with a chant "Russia will be free!" that was repeated by the crowd.
A small scuffle erupted when a small group of pro-Putin activists shouted provocative slogans. Police escorted them away.
A few hours before the rally, a man helping construct the stage for the protest was killed by sound equipment that collapsed on him. Officials have started a probe into the incident.