A Moscow district court has ordered the closure of the foundation crucial to the failed election campaign of opposition leader Alexei Navalny.

Navalny, President Vladimir Putin's most formidable foe, had been leading a grass-roots campaign for a year ahead of the 2018 presidential vote, before election officials in December formally barred him from running. Navalny then vowed to mount a boycott campaign to lower the voter turnout, which would be an embarrassment for the Kremlin.

The Moscow court ruled on Monday that the foundation Navalny and his allies have used to rent premises and pay salaries at campaign headquarters should be shut down. The lawsuit was filed by prosecutors who said they found numerous violations at the foundation.

Navalny's campaign chief Leonid Volkov on Twitter described the ruling as absurd and vowed to appeal.