Polls have opened in the Russian capital, Moscow, for mayoral elections seen as a key political barometer for the whole country. Main challenger Alexei Navalny is one of President Vladimir Putin's most vocal critics.
The election sees anti-corruption blogger Navalny take on the incumbent mayor and Putin ally Sergei Sobyanin, who has held the post since 2010.
About 40 million people, or half of all Russian voters, are eligible to cast ballots in local-body elections across Russia. The polls are the biggest political test for Putin since he faced down mass protests a year and a half ago.
In Moscow opinion surveys show Sobyanin, 55, more than 60 percentage points ahead of Navalny, who has been trailing on around 20 per cent.
But the election marks the first time an opposition leader has managed to stand in a high-profile poll, making it the first truly competitive electoral contest in many years in Russia.
Tension hangs over Moscow's vote because Navalny, 37, was sentenced to prison for five years on July 18 on charges of embezzlement. In an unprecedented move, he was released the next day on bail following a complaint by prosecutors.
Differences at the top?
Observers of the Kremlin have put his release down to growing differences between hard-liners and reformers at the top level of Russian politics. They also say his five-year term may be commuted to a suspended sentence if he performs well in the poll.
Navalny's supporters see the sentence as a political punishment for his role in organizing huge anti-Putin demonstrations in the winter of 2011-2012. The protests were sparked by widespread claims of fraud in parliamentary elections and discontent at Putin's decade-long rule.
Moscow gave Putin just 46.95 percent of the vote at the 2012 presidential election, well below the national average.
Navalny, a lawyer, made a name for himself as a blogger exposing corruuption among the elites. He has promised to jail Putin and his allies if he is one day elected as president.
Despite Navalny's growing political prominence, Putin refuses even to mention him by name, referring to him only as "this gentleman."
Putin praises Sobyanin
Ahead of the election, the Russian president has profusely praised Sobyanin, his former chief of staff, telling Channel One television: "He speaks less and does more. I love such people."
Sobyanin was appointed to the post of mayor in 2010 after then-president Dmitry Medvedev fired longtime mayor Yuri Luhkov. He formerly served as governor of Siberia.
Four other candidates are also running in the polls, but none of them has significant support.
tj/ (AFP, dpa)