Russia has urged its citizens not to take part in "unauthorised" demonstrations to support jailed Kremlin critic Alexei Navalny.
Allies of Navalny have called on his supporters to protest in residential courtyards on Sunday and post pictures of it on social media.
But Russia's Interior Ministry has reiterated its appeal for citizens not to "participate in unauthorised rallies".
It's unclear whether the ministry is referring to public protests or the ones planned in residences.
"We remind you that restrictive measures continue to operate in the regions due to the difficult epidemiological situation," the ministry stated on Thursday.
Russia's General Prosecutor’s Office and Investigative Committee have also issued statements, warning that citizens could face criminal charges by protesting.
The Interior Ministry added that 90 criminal cases have been opened in relation to unauthorised demonstrations since the start of the year.
"Persons who have committed violent acts calling for group violations of public order who do not comply with the lawful demands of the police will be detained and brought to justice," the statement said.
Russia has rejected international criticism of the imprisonment of Navalny, which the Kremlin has described as an internal matter.
The leading opposition figure was detained by police in Moscow on January 17 when returned to the country from Germany after recovering from a poisoning he blames on the Kremlin.
He was recently handed a 3.5-year jail sentence, part of which he has already served, for violating the terms of his probation.
Since his return to Russia, tens of thousands of Russians have demonstrated in support of Navalny, which resulted in a heavy-handed police crackdown and more than 11,000 arrests.
On Thursday, the Council of Europe Commissioner for Human Rights Dunja Mijatovic called on the Russian Interior Minister to put an end to the arrests of peaceful demonstrators.
In a letter to Vladimir Kolokoltsev, the commissioner called for "an immediate halt to the arrests of citizens exercising their right to demonstrate peacefully and to bring the policing of demonstrations in line with human rights".
Mijatovic also noted reports that Russian police "made arbitrary arrests during the demonstrations, regardless of the attitude of the demonstrators".
"Such a situation, if confirmed, amounts to inhuman and degrading treatment and should stop immediately," said Mijatovic.
Several human rights organisations recorded dozens of cases, including journalists, who "were beaten or suffered injuries, some of them serious", the letter added.