European Union foreign policy chief Catherine Ashton urged Russia to review its decision to bar liberal opposition leader Grigory Yavlinsky from taking part in the country’s upcoming presidential election.

Yavlinsky, leader of the liberal Yabloko party and two-time presidential candidate, was disqualified last week after officials judged that 25.6 percent of the 2 million signatures submitted as part of his application were invalid or fake.

“I call on the responsible authorities to review as a matter of urgency the decision not to register Grigory Yavlinsky,” Ashton said during the European Parliament’s debates on Russia in Brussels.

Yavlinsky denied the accusations of fake signatures, saying the ban was a “purely political decision” aimed at preventing Yabloko from deploying its election monitors at the March 4 vote which is widely predicted to land Prime Minister Vladimir Putin with his old job in the Kremlin.

Ashton also said that Russia might see larger civilian protests on February 4, compared with the protests in December.

“On the protesters that began in December we've seen are set to continue. The movement has grown; we can expect a large mobilization this Saturday, the 4th February,” she said.

Opposition activists maintain Putin could not avoid a second round without widespread fraud. Claims of ballot-stuffing in favor of Putin’s United Russia party at the December 4 parliamentary election triggered the biggest anti-government protests seen in Russia since Soviet times.

Oppositionists will gather for more rallies demanding fair presidential elections this Saturday.