"The party appealed to the Supreme Court on Wednesday to demand that Vladimir Putin be removed from United Russia's list of candidates for the State Duma for repeated violations of the law," said Nikita Belykh, leader of the Union of Right Forces.
Vladimir Putin tops ruling United Russia's list of candidates for the December 2 parliamentary elections to the lower house. Critics accuse Putin of using administrative resources to promote the party.
Belykh said the Kremlin had "used all opportunities provided by the state machinery" to lessen the chances of other parties.
Latest opinion surveys put United Russia in the lead with 57-59% of popular support. The Communist Party and the nationalist Liberal Democratic Party are the other two players expected to make it into the State Duma, enjoying up to 9% and 7% of support respectively. No other parties are expected to overcome the 7% threshold.
Putin, credited in Russia for bringing stability and presiding over economic growth, has repeatedly rejected supporters' proposals to run for a third consecutive presidential term in the March 2008 elections and amend the Constitution to this end.
However, political commentators continue to discuss possible loopholes that would allow Putin to run without violating the Constitution.
