Russian Prime Minister Vladimir Putin says the opposition lacks goals and leaders, and he has rejected demands for a rerun of Russia's recent parliamentary elections.

In comments to his supporters Tuesday, Mr. Putin said the opposition has no unified program, no clear way of reaching its aims and nobody who can achieve something “concrete.”

Mr. Putin also said he wants Russia's March presidential election to be absolutely transparent and insisted he does not need vote rigging to win the poll.

Alleged voter fraud in the December 4 Russian parliamentary elections has spurred the largest protests since the collapse of the Soviet Union 20 years ago.

Activists say Mr. Putin's United Russia party illegally won a narrow majority through voter fraud. They want to throw out the results and hold a new vote.

Meanwhile, Russian President Dmitry Medvedev has appointed a top Kremlin official to the post of deputy prime minister, as part of a government reshuffling following the elections. Vladislav Surkov previously served as Kremlin first deputy chief of staff.

Activists also say measures are needed to prevent more fraud in Russia's presidential election in March, when Mr. Putin hopes to return to the post he held from 2000 to 2008.

Organizers of a protest in Moscow on Saturday say more than 100,000 people joined the rally in below-freezing temperatures, exceeding the size of a similar protest earlier this month. Russian police estimated the turnout at about 28,000 people.

The Moscow demonstrations and smaller anti-Putin rallies in other cities are the largest show of discontent in Russia since the 1990s. Mr. Medvedev has responded by promising reforms to allow more competition in elections beyond 2012. He is stepping down in March to make way for Mr. Putin's candidacy.