Russia's prime minister has belittled the country's protest movement as lacking clear aims or leaders and rejected their demands for a review of the results of disputed parliamentary polls.
"They have no united programme, clear ways of reaching their aims - which are themselves not clear - or people who could achieve something concrete," Vladimir Putin said in comments broadcast by state television.
Putin said the protest movement was more interested in creating instability than achieving specific aims, comparing their strategy to "Brownian motion" - the theory on the random movement of particles.
"I have difficulty imagining who from their ranks could do concrete work for the development of our state," Putin told a meeting of his All-Russian Popular Front that rallies support for him.
Meanwhile, Putin said that the March presidential election, in which he'll compete, should be transparent and fair.
He bluntly rejected the protestors' most pressing demand - a review and re-run of the December 4 polls for the State Duma lower house of parliament won by the ruling United Russia party, but which the opposition says was rigged.
"The elections are over. The parliament has started its work and a speaker elected. The State Duma is working ... There can be no talk of any review," Putin said. "There is only one way prescribed by law - an appeal to court," he said.
But Putin said it was necessary to lift any "insinuations" that there would be fraud in the March 4 presidential polls and vowed that there would be increased transparency if required.
Putin is facing the biggest challenge of his 12-year domination of Russia as he heads into March 4 presidential elections after two mass protests against the conduct of allegedly rigged parliamentary polls.
Tens of thousands of people rallied in central Moscow on Saturday for the second time in an action that was both bigger and more directly aimed against Putin than the first protest on December 10.
Alexei Navalny - a lawyer who won prominence with investigations of state corruption and one of the figureheads of the anti-Putin movement- said in an interview late on Monday he would be prepared to challenge Putin in fair elections.
Navalny can no longer register for the presidential ballot because the deadline expired earlier this month but he told Moscow Echo radio in an interview he would challenge Putin if the elections were fair.
"When we get a chance to take part in elections, I am ready to fight for leading positions, including in the presidential vote," he said.
"This [March 4] vote that we will be having will not be an election. They will be illegitimate no matter what happens. We will never recognise them," Navalny said.
Former finance minister Alexei Kudrin told the Vedomosti daily that he had met Putin on the eve of Saturday's mass rally in Moscow and advised him that "urgent dialogue was needed" with the protesters.
The leaders of the protest movement have not yet said when the next demonstration will take place but they have indicated it will not be before the end of the New Year holidays in mid-January.
However huge anger has been sparked by the additional 10-day jail sentence handed to Sergei Udaltsov, an ultra-left wing activist who had already served a term in prison for taking part in a rally earlier this month.
More than 1,700 people have vowed on Facebook to attend a rally on Thursday at Pushkin Square in Moscow "for the release and life of Udaltsov and all political prisoners" amid growing concerns over his health.