The Kremlin has warned leading Russian opposition politician Alexei Navalny not to wage a protest campaign over his exclusion from March’s presidential elections, raising the prospect of a wider crackdown against those seeking to challenge President Vladimir Putin.

Mr Navalny was formally barred from standing by the Central Election Commission, which on Monday said he was ineligible due to a criminal conviction. Shortly after the commission’s decision, the anti-corruption blogger called for a boycott of the election and threatened countrywide street protests.

“Appeals for a boycott, of course, are subject to very scrupulous examination of whether they comply with or contradict the law,” Dmitry Peskov, Mr Putin’s spokesman, said on Tuesday. He rejected charges by critics that Mr Navalny’s exclusion would undermine the legitimacy of the upcoming race.