Russia yesterday rejected concerns that the decision to bar opposition leader Alexei Navalny from running against President Vladimir Putin in a March election could undermine the vote's legitimacy.

Navalny is seen by many as the only Russian opposition leader who stands a fighting chance of challenging Putin.

Observers say barring him from running in the polls undermines the legitimacy of the vote and could affect voter turnout.

The European Union weighed in on the controversy Tuesday, saying the refusal to register Navalny cast "serious doubt" on the election.

'VOTE STRIKE' URGED

Russia's Central Election Commission on Monday rejected Navalny's bid to take on Putin in the poll, citing a controversial embezzlement conviction.

The 41-year-old lawyer maintains that the criminal case against him is politically motivated. He urged his supporters to stage a "vote strike" instead.

Critics say banning Navalny would undermine the legitimacy of the vote.

"We cannot agree with this point of view," Putin's spokesman Dmitry Peskov said.

He insisted that barring Navalny from running "can in no way affect the legitimacy of the election".

Peskov also said any calls to boycott the election should be "rigorously studied" -- a thinly veiled threat of punishment.

'LEVEL-PLAYING FIELD'

EU external services spokeswoman Maja Kocijancic said the ban on Navalny "casts a serious doubt on political pluralism in Russia and the prospect of democratic elections next year."

“Politically-motivated charges should not be used against political participation," she said in a statement on Tuesday.

"We expect the Russian authorities to ensure that there is a level playing field, including in the presidential elections that will take place on 18 March."

The Council of Europe's decision-making body, the Committee of Ministers, has urged Russia to allow Navalny to stand for election despite what it called his "arbitrary and unfair" fraud conviction.