Several thousand opposition supporters have gathered in central Moscow for an unauthorised rally and at least one prominent opposition figure has been detained.
Opposition leaders had applied for permission to hold a march marking a year since a wave of massive protests against Vladimir Putin and the government arose, but city authorities refused to allow the gathering.
There was a heavy police presence around the approximately 3,000 activists who came to Lubyanka Square for the rally.
The square is outside the headquarters of the Federal Security Service, the main successor agency of the Soviet KGB.
Sergei Udaltsov, leader of the Left Front and one of the most active opposition figures, was detained.