Police in Moscow have arrested anti-Kremlin opposition leader Boris Nemstov and at least 95 other activists have been held during demonstrations across Russia.
The simultaneous protests were organised by rights groups demanding freedom of assembly.
Marchers held placards emblazoned with the number 31, a reference to the Russian constitution’s Article 31, which guarantees the right to hold peaceful gatherings.
The campaigners hold their rallies on the last day of every month with 31 days in it to symbolise
their movement which is called Strategy 31.
Meanwhile in Kiev about 30 Ukrainian activists from the “Orange Revolution Coalition” handed out ribbons.
Police moved in when some of them smeared a train with orange paint as they waved off members of their group who were going to join an anti-Kremlin demonstration in Russia in an act of solidarity.
The colour was used by the leaders of the pro-western Orange Revolution that swept to power in Ukraine after mass street protests in 2004.