Russian voters go to the polls across several time zones on Sunday to elect a new president.
Former president Vladimir Putin (2000-2008) hopes to return to the post after spending four years as prime minister, a step he took to abide by the constitution.
He faces four challengers, three of whom he defeated in previous elections.
The BBC reports the election is being held amidst a backdrop of popular discontent, sparked by accusations of fraud during elections for the State Duma (parliament) in December.
Recent demonstrations in Moscow and other major cities attracted more than 50,000 people. Similar numbers attended pro-Putin and pro-Communist rallies.
Mr Putin has responded by announcing a programme to install webcams in all polling stations, but critics have questioned their effectiveness. There are 90,000 polling stations.
Polls will be open from 8am - 8pm in each time zone, with the first opening in the Far East of the country and the last in the western Kaliningrad region.
Russian media report the Interior Ministry is bringing 6000 police reinforcements to Moscow from the regions.
A joint mission by the Organisation for Security and Co-operation in Europe and the Parliamentary Assembly of the Council of Europe, comprising 250 observers, is monitoring the elections.