MOSCOW:Supporters of jailed Kremlin critic Alexei Navalny took to the streets in Russia's Far East on Saturday to demand his release on a day of nationwide protests that authorities have declared illegal and vowed to break up.

Navalny called on his supporters to protest after being arrested last weekend when he returned to Moscow for the first time after being poisoned in August with a military-grade nerve agent. Navalny had been treated in Germany.

Video footage from Vladivostok showed riot police chasing a group of protesters down the street, while demonstrators in Khabarovsk, braving temperatures of around -14 degrees Celsius (7 degrees Fahrenheit), chanted "Shame!" and "Bandits!"

The OVD-Info monitoring group said that 48 people, including 13 in Khabarovsk, had been detained so far at the rallies.

In Moscow, police erected barricades around Pushkinskaya Square as workers were engaged in re-tiling it, an apparent attempt to thwart a demonstration scheduled to start at 1100 GMT.

Navalny, an ex-lawyer who has accused President Vladimir Putin of ordering his murder, could face years in jail over legal cases that he calls trumped up. Putin has denied involvement.

Navalny's supporters are hoping they can produce a show of anti-Kremlin street support despite winter conditions and the coronavirus pandemic to pressure the authorities into freeing him.

The West has told Moscow to let him go, sparking new tensions in already strained Russia ties as U.S. President Joe Biden launches his administration.

In a push to galvanise support ahead of the protests, Navalny's team released a video about an opulent palace on the Black Sea they alleged belonged to Putin, something the Kremlin denied. As of Saturday the clip had been viewed more than 65 million times.

Police have cracked down in the run-up to the rallies, rounding up several of Navalny's allies they accused of calling for illegal protests and jailing at least two of them, including Navalny's spokeswoman, for more than a week each.

Authorities also announced a criminal investigation against Navalny supporters over calls urging minors to attend illegal rallies that it said were made on various social networks.

Navalny's allies hope to tap into what polls say are pent-up public frustrations over years of falling wages and economic fallout from the pandemic. But Putin's grip on power looks unassailable and the 68-year-old president regularly records an approval rating of over 60%, many times higher than that of Navalny.

The U.S. Embassy published the locations and times of the protests, telling Americans to stay away. Russia's foreign ministry called this a "gross interference" in the country's domestic affairs.