MOSCOW - Russian Prime Minister Vladimir Putin on Tuesday belittled Russia'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 program, clear ways of reaching their aims - which are themselves not clear - or people who could achieve something concrete," Putin said in comments broadcast by state television.

"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.

He bluntly rejected the protesters' most pressing demand - a review and re-run of the Dec 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 alleged there would be fraud in the March 4 presidential polls and vowed that there would be increased transparency if required.

"I, as one of the candidates, need no tricks. I want to have the will of the people and their trust. Without that there is no point in working," he added.

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 outcome of parliamentary polls.

Alexei Navalny - a lawyer who won prominence with investigations of state corruption - said in an interview late on Monday he would be prepared to challenge Putin in fair elections. Navalny has become one of the figureheads of the anti-Putin movement.

But 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.

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 Dec 10.

Agence France-Presse