Jailed opposition politician Alexei Navalny on Thursday denounced Kremlin pressure and a biased judiciary during a hearing in which he was ordered to remain behind bars ahead of anti-government protests this weekend.

Several of his allies were detained following police raids on their apartments and offices hours before the verdict and in the run-up to Sunday's rally outside the FSB security service's headquarters in the Russian capital.

"This is blatant lawlessness to intimidate me and other people," Navalny told the court via video link from Moscow's Matrosskaya Tishina, a high-security detention centre.

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

Later in the day President Vladimir Putin's top domestic critic issued a new call for nationwide protests.

"Don't be afraid of anything," he wrote from jail. "The majority is on our side. Let's wake them up."

Police detained the 44-year-old anti-graft campaigner at a Moscow airport after he returned to Russia on January 17 from Germany, where he had been recovering from a near-fatal poisoning with a nerve toxin.

A makeshift court at a police station last week ordered Navalny placed in custody until February 15.

Timeline of the poisoning of Russian opposition campaigner Alexei Navalny
Timeline of the poisoning of Russian opposition campaigner Alexei Navalny AFP / Gal ROMA

His lawyer Olga Mikhailova said she intended to appeal the decision, but that "hopes are not high" for success.

Police on Wednesday carried out searches at Navalny's flat in Moscow and the homes of his allies over alleged violations of coronavirus restrictions during last week's protests.

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

Ivan Zhdanov, the head of Navalny's Anti-Corruption Foundation (FBK), said prominent aide Lyubov Sobol and Navalny's brother Oleg were detained for 48 hours as suspects in a probe launched by the interior ministry.

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

Police also arrived at the home of Navalny's doctor Anastasia Vasilyeva, who was detained for 48 hours too.

In a video posted on Twitter, the doctor was playing Beethoven on a piano as people in uniform arrived at the door.

Alexei Navalny appeared in court via video link from prison, where he has been held since January 17
Alexei Navalny appeared in court via video link from prison, where he has been held since January 17 AFP / Alexander NEMENOV

Tens of thousands of people across Russia rallied last weekend in support of Navalny, who is facing charges of violating the terms of a 2014 suspended sentence and could be jailed for two-and-a-half years.

Officials have threatened to fine social media including Instagram, Twitter and TikTok for failing to delete posts urging young people to join the rallies.

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

Kremlin spokesman Dmitry Peskov told reporters that the state did not want social networks to become "platforms to announce illegal protests".

The Investigative Committee, which probes major crimes, said it had launched a probe against Leonid Volkov, the head of Navalny's regional network, for persuading young people to protest.

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 in the poisoning attack on Putin's orders.

More than 4,000 people were detained last weekend at the unsanctioned rallies, which have sparked a series of criminal investigations.

Rights group Amnesty International on Thursday said Russian authorities "appear shamelessly bent on violating human rights by silencing their critics" and called their actions a "cowardly attempt" to prevent further protests in support of Navalny.

The Moscow prosecutor's office sent out warnings ahead of Sunday's rally to six individuals and five internet platforms, without naming them.

Moscow police also warned Russians against staging protests this weekend, saying demonstrators could face criminal responsibility.

The opposition appears unwilling to back down, however.

Volkov said on Telegram Sunday's rallies will take place "despite searches and late-night interrogations, despite the 4,000 arrests last week, despite the lies and intimidation of Kremlin propaganda".

Political analyst Alexander Baunov of the Carnegie Moscow Center told AFP that Navalny's continued protest of the government was evidence that he was "ready to pay the price to become a real counterweight to Putin".