Moscow police and city officials have warned the Communist Party against following through with calls for a gathering in the Russian capital on September 25 to protest the results of last weekend's elections.
Russia's media regulator, Roskomnadzor, has also ordered the publishers of the party's website to delete references to such an event, according to two Communist candidates.
Doubts have persisted among rivals of the ruling United Russia party and outside observers over the September 17-19 State Duma elections in the face of bans on opposition candidates and allegations of irregularities that helped propel President Vladimir Putin's allies to a new supermajority.
But Russia's Central Election Commission announced on September 24 that it had validated the election results.
Commission Chairwoman Ella Pamfilova announced that United Russia won 324 seats in parliament -- 19 fewer than in 2016 but enough to allow it to change the constitution and cement Putin's grip on power ahead of a possible run in the 2024 presidential election.
The Communists have insisted publicly that their event on September 25 is a meeting of deputies and therefore does not require official approval.
But the Moscow mayor's office, the prosecutor's office, and city police have all issued warnings against unsanctioned activities, and said participants will be held accountable.
Reports quote city officials as saying gatherings violate anti-pandemic restrictions.
Roskomnadzor, meanwhile, sent a letter threatening to block the Communist Party website over its posting of details of the planned gathering.
Many opposition allies of jailed Kremlin critic Aleksei Navalny had been barred from running for office and accused the authorities of censorship.
Navalny's Smart Voting election-guide app, intended to evade United Russia's stranglehold on state media and politics, disappeared from the Apple and Google online stores on September 17, the day voting started.
Moscow police on September 23 detained municipal deputy Sergei Vlasov and two other participants in a Communist Party demonstration on Pushkin Square three days earlier.
Ekho Moskvy quoted opposition Left Front leader Sergei Udaltsov as saying he was also detained on September 24.
Meanwhile, Moscow police on September 24 announced the administrative prosecution of 30 participants in the Pushkin Square demonstration against the election results.
A group of independent municipal and regional deputies has launched a petition demanding all results from all of the elections throughout Russia be invalidated due to numerous violations and irregularities in the voting.
With reporting by Ekho Moskvy
