The dispute comes as the Kremlin is struggling with how to deal with opposing views in the sprawling capital of 12.6 million people.
Russian police have detained hundreds of people outside the Moscow mayor’s office ahead of an election protest demanding that opposition candidates be allowed to run for the Moscow city council.
There was no immediate information on what charges the detainees might face.
Alexei Navalny, Russia’s most prominent opposition figure, called for the protest and was sentenced on Wednesday to 30 days in jail for doing so.
On Saturday, several opposition members were detained throughout the city, including Ilya Yashin, Dmitry Gudkov and the top Navalny associate Ivan Zhdanov.
The police presence was heavy at the mayor’s office on Tverskaya Street, one of Moscow’s main thoroughfares, with police trucks and buses parked in the building’s courtyard and other buses positioned nearby to take detainees away.
The decision by electoral authorities to bar some opposition candidates for allegedly insufficient signatures on nominating petitions had already sparked several days of demonstrations this month.
Moscow city council, which has 45 seats, is responsible for a very large municipal budget and is controlled by the pro-Kremlin United Russia party. All of its seats, which have a five-year term, are up for election on 8 September.