A few dozen anti-government activists held a sit-down protest in Triumfalnaya Ploshchad on Sunday.
It was the latest in a series of protests that opposition leaders call on the last day of every month with 31 days in reference to the 31st Article of the Constitution, which guarantees freedom of assembly.
The tactic of sitting down, however, was new and appeared to be an attempt to demonstrate that the protest would be peaceful.
Moscow police also appeared to have taken a new approach. The police usually break up opposition protests, but they said they would not detain activists Sunday as long as they posed no danger to pedestrians.
In St. Petersburg, however, the police forcefully broke up a similar rally and roughly made a number of detentions.