Tens of thousands of Russians have flooded Moscow city centre to demand an end to Vladimir Putin's rule.

The crowds braved sub-zero temperatures to keep the protest movement alive a month before a presidential election Mr Putin is still expected to win.

The protest - which drew 120,000 people, according to organisers - was the third mass demonstration since Mr Putin's party won a parliamentary election on December 4 with the help of what appeared to be widespread fraud.

The election and Mr Putin's presumptuous decision to reclaim the presidency proved the last straw for Russians increasingly unhappy with the creeping authoritarianism during his 12-year rule. The protest rallies - which have brought together liberals, leftists and nationalists - are the biggest in Russia since the demonstrations 20 years ago that led to the collapse of the Soviet Union.

People wearing the white ribbons that have become the symbol of the protest movement and chanting "Russia Without Putin" braved temperatures as low as minus 20C as they marched less than a mile to a square across the river from the Kremlin where the rally was held. Thousands of police monitored the peaceful protest without intervening.

An anti-Putin protest also took place in St Petersburg, drawing 5,000 people, and smaller rallies were held in several dozen other cities across Russia.

A separate rally in Moscow in support of Putin drew no more than 20,000 people. Most of them were teachers, municipal workers, employees of state-owned companies or trade union activists, who had come with co-workers on buses provided by their employers.

The anti-Putin protests have been driven by members of the educated and urban middle class.

Mr Putin has ignored many of their demands, including for a repeat election, but he has sought to assuage their anger by making vague promises to introduce liberal reforms and to guarantee a fair presidential vote on March 4.

The protest leaders hope to stage another rally a week before the election to keep up the pressure on Mr Putin.