Several allies of jailed Kremlin critic Alexei Navalny were taken into custody early on Thursday after their apartments and offices were searched by police ahead of planned demonstrations.

Navalny's aides indicated that the searches were connected to a criminal probe launched by the interior ministry over alleged violations of coronavirus restrictions during protests last week.

The searches come as the opposition called for fresh demonstrations on Sunday to demand freedom for Navalny, who was arrested on his return from Germany, where he spent months recovering from a nerve agent poisoning.

Police searched several apartments and offices linked to Navalny
Police searched several apartments and offices linked to Navalny AFP / NATALIA KOLESNIKOVA

Ivan Zhdanov, the head of Navalny's FBK Anti-Corruption Foundation, said prominent aide Lyubov Sobol and Navalny's brother Oleg were detained for 48 hours as suspects.

Sobol's lawyer Vladimir Voronin said both she and Oleg Navalny were questioned by police during the night.

Searches were also carried out in the flat of Navalny's wife Yulia and in the office of FBK, Navalny's organisation, which is known for its investigations into the wealth of Russia's elites.

Timeline of the poisoning of Russian opposition campaigner Alexei Navalny to his arrest shortly after arrival at Moscow airport.
Timeline of the poisoning of Russian opposition campaigner Alexei Navalny to his arrest shortly after arrival at Moscow airport. AFP / Gal ROMA

Police also arrived at the home of Navalny's doctor Anastasia Vasilyeva and she too was taken into custody for 48 hours.

In a video posted on Twitter by Vasilyeva's press secretary, the doctor is playing Beethoven on the piano as people in uniform arrive at the door.

According to Mediazona, a news website that focuses on opposition detentions, police carried out at least 18 searches on Wednesday.

IMAGESRussian police are present at the Moscow apartment of Yulia Navalnaya, wife of jailed Kremlin critic Alexei Navalny. His team said police were searching flats linked to Navalny and the foundation's offices for alleged violations of coronavirus restr
IMAGESRussian police are present at the Moscow apartment of Yulia Navalnaya, wife of jailed Kremlin critic Alexei Navalny. His team said police were searching flats linked to Navalny and the foundation's offices for alleged violations of coronavirus restrictions. AFPTV / Nikolay KORZHOV

Last weekend tens of thousands of Russians across the country rallied in support of Navalny who is awaiting a trial that could see him imprisoned for several years on charges of violating a 2014 suspended sentence.

Navalny's lawyers intend to appeal against his arrest later on Thursday.

Protests in Russia are banned if they are not approved by the authorities, as are calls for people under 18 to join in.

The Investigative Committee, which probes major crimes, said on Thursday it launched a probe against Leonid Volkov, the head of Navalny's regional network, for persuading minors to commit "illegal actions".

The opposition plans to hold more rallies on Sunday, which in Moscow will take place outside the headquarters of the FSB, the security agency that Navalny says targeted him with a near-fatal poisoning attack.

More than 3,900 people were detained last Saturday at the unsanctioned rallies, which have sparked a series of criminal investigations.