Russia's
opposition is due to hold new mass rallies in Moscow and other cities to protest against
what it says were rigged elections on 4 December.
In the capital alone, organisers say some 50,000 people are expected to
gather on Sakharov Avenue.The protesters are demanding a re-run of the poll, which was won by the party of Prime Minister Vladimir Putin.
President Dmitry Medvedev announced political reforms this week, but many demonstrators say it is not enough.
'On the backfoot'
The Moscow
rally - authorised by the authorities - is being organised by a coalition of
opposition forces.Some 47,000 people have already vowed on Facebook to attend, and another 10,000 say they may join the demonstration.
Among those attending the event will be prominent anti-Kremlin blogger Alexei Navalny, following his release from prison after taking part in another demonstration in Moscow on 10 December.
Organisers said that as many as 50,000 people rallied on that day, in what was the biggest anti-government protest since the fall of the Soviet Union in 1991.
The opposition has been encouraged by that success, forcing the Kremlin on the backfoot.
However, one of the main problems for the opposition is that there is no single leader able to unite it, our correspondent adds.
According to the official results of the elections to Russia's Duma, the ruling United Russia party saw its share of the vote fall from 64% to 49%, though it remains easily the biggest party.
But there is a widespread view, fuelled by mobile phone videos and accounts on internet social networking sites, that there was wholesale election fraud and that Mr Putin's party cheated its way to victory.
The Kremlin denies the claim.
