MOSCOW (Reuters) - The Kremlin said on Tuesday a call by opposition leader Alexei Navalny to boycott next year’s presidential election must be checked to see if it complies with the law, paving the way for possible police action against him and his supporters.

Russian opposition leader Alexei Navalny submits his documents to be registered as a presidential candidate at the Central Election Commission in Moscow, Russia December 24, 2017. REUTERS/Tatyana Makeyeva

Navalny called on Monday for a boycott of the March 18 election after Russia’s central election commission ruled he was not eligible to run for president due to a suspended prison sentence hanging over him.

“The calls for a boycott will require scrupulous study, to see whether or not they comply with the law,” Kremlin spokesman Dmitry Peskov told reporters on a conference call.

Declining to comment on the election commission’s decision, Peskov shrugged off allegations that the presidential poll would be a farce without Navalny.

“The fact that one of the would-be candidates is not taking part has no bearing on the election’s legitimacy,” said Peskov.

Navalny, a 41-year-old lawyer, has repeatedly said the suspended sentence handed to him in an embezzlement case was politically motivated.

On Monday Navalny said millions of voters would be disenfranchised without his participation in the election, which opinion polls show incumbent Vladimir Putin winning comfortably.

The European Union also questioned the Russian election commission’s decision to bar Navalny.

“(It) casts a serious doubt on political pluralism in Russia and the prospect of democratic elections next year,” the EU’s External Action Service said in a statement on Tuesday.

“Politically motivated charges should not be used against political participation,” it said, urging Moscow to ensure a “level playing field” for all Russian elections.

Putin, 65, has dominated Russia’s political landscape for the last 17 years and if, as expected, he wins next year’s election would be eligible to serve another six years until 2024, when he turns 72.

Allies laud Putin as a father-of-the-nation figure who has restored national pride and expanded Moscow’s global clout with interventions in Syria and Ukraine.

Navalny says Putin’s support is exaggerated and artificially maintained by a biased state media and an unfair system which excludes genuine opponents. He says he could defeat him in a fair election, an assertion Putin’s supporters have laughed off.

Navalny has been jailed three times this year and charged with breaking the law for organizing public meetings and rallies designed to bolster his presidential campaign.