Over 200 people were detained Monday by police at opposition protests called by Kremlin critic Alexei Navalny, said a Russian NGO tracking arrests.

"About 121 people were detained in Moscow up to this point. In Saint-Petersburg - 137," OVD-Info wrote on Twitter, following other reports of detentions in far-eastern Vladivostok and southern resort Sochi, and the detention of Navalny himself.