Security forces blanket Moscow
A huge security operation has covered Moscow in a show of force following protests over scandal-marred elections that saw Prime Minister Vladimir Putin's party struggle to keep a majority.
Demonstrations on Monday and Tuesday were an unusually sustained show of indignation for the Russian opposition. The thousands of Russians who rallied in Moscow and St Petersburg faced police and Interior Ministry troops, who detained hundreds of protesters.
Sunday's parliamentary vote suggested Russians are tiring of Mr Putin and his United Russia party and allegations of vote-rigging have fired up the opposition, which has long seen its protests crushed and its pleas ignored by the Kremlin-dominated media.
At least 300 people were detained by police at a protest in central Moscow on Tuesday night.
About 200 were arrested at a similar attempt to hold an unsanctioned rally in St Petersburg and another 25 in the southern city of Rostov-on-Don.
Meanwhile Mr Putin officially registered on to run for the presidency in March, but the unusually sustained protests of the past two days showed the indignation of the Russian opposition and suggested his drive to retake the job he held from 2000-2008 may not go as smoothly as expected.