United Russia, President Vladimir Putin’s party, is expected to tighten its grip on the country, following the results of Sunday’s regional election.
The party is likely to win most of the nearly 5,000 contests as opposition groups complain they have been kept off the ballot by new registration rules.
Two prominent anti-Putin politicians claim that electoral registers in their constituencies have been illegally inflated to ensure more support for United Russia.
Election chiefs have dismissed their accusations as nonsense.
The vote is still seen as Putin’s first major test since being restored as head of state five months ago.
Voters from 77 Russian regions from the Baltic to the Sea of Japan have been out in force to pick their town Mayor. Also up for re-election are five of the country’s 83 powerful regional governors.