Russian opposition forces have set up a working group which will begin collecting signatures on a petition demanding that the National Supreme Court annuls the outcome of the Dec. 4 parliamentary elections, Mikhail Shneider, member of Solidarity opposition movement said on Tuesday.

Allegations of widespread fraud in the recent elections that gave Prime Minister Vladimir Putin’s United Russia party a parliamentary majority have galvanized massive street protests in opposition to the Russian political establishment.

On December 24, mass protest on Moscow’s Sakharov Avenue brought together up to 100,000 people according to the organizers of the protest, while police say just 30,000 people attended. The protesters demanded new parliamentary elections and want liberal reforms in Russia.

Activists collected first signatures in support of the petition to the Supreme Court during the protest on Sakharov Avenue.

In his first reaction to the protest, Putin said that a review of the results of the parliamentary elections is impossible.

“Any talks about reviewing the results of the elections are impossible, except one way, a court appeal,” Putin said after the protests.

Volunteers will circulate petitions asking people to require that the National Supreme court annuls Dec. 4 parliamentary polls, Shnedider said.

The final text of the petition to be sent to the court is now being prepared by lawyers. “It will be ready by mid-February,” he added.