Photos: Russia protest

Police broke up a crowd of about 2,000 opposition supporters and onlookers and arrested scores of people.  (Sergei L. Loiko / Los Angeles Times)

Police arrest a demonstrator. The clash was part of a ritual that has seen demonstrators gather on the 31st day of the month in Triumfalnaya Square to press for the right of free assembly as enshrined in Article 31 of the Russian Constitution.  (Sergei L. Loiko / Los Angeles Times)

Police push opposition demonstrators off Triumfalnaya Square. “Permission from local authorities is needed” for a demonstration, Putin said in an interview published Monday by Kommersant, a popular daily newspaper. “If you come out without permission, have a club on the head, that is all.”  (Sergei L. Loiko / Los Angeles Times)

Demostrators inside a police bus. The number refers to Article 31 of the Russian Constitution.  (Sergei L. Loiko / Los Angeles Times)