Russian police detained people from a crowd of about 200 protesters Sunday in Saint Petersburg who had gathered over the crackdown on the Rohingya Muslims in Myanmar.
The square in the city centre was surrounded with police vans and policemen were leading people away into the vans, an AFP correspondent at the scene said, counting over 100 detained at the unauthorised demonstration.
"Our brothers are being detained! Why are Muslims always to blame, why are they detaining us?" one protester shouted.
"Why can't we express ourselves," complained another protester, Makhmud, 45. "We are worried about what is happening with our brothers in Myanmar."
The plight of the Rohingya minority in Myanmar, where nearly 300,000 have fled their homes from what they say are state-orchestrated mass killings into neighbouring Bangladesh, has seen Russia's Muslims stage several protests, particularly after a call by Chechen strongman Ramzan Kadyrov.
Thousands rallied in Chechnya's main city Grozny last week as Kadyrov called on Moscow to "stop this bloodshed" in a rare break from his public image as a fervent loyalist of President Vladimir Putin.
Moscow however has been mute over Myanmar. "We're against any sort of violence," Putin said Tuesday when asked about Kadyrov's position, adding that "any person has a right to his opinion regardless of his post."
Russia and Myanmar are also allies who signed a military cooperation agreement last year.