Supporters of jailed Kremlin critic Alexei Navalny took to the streets in Siberia and the Russian Far East on Sunday for a second straight weekend despite a sweeping crackdown on his allies and warnings from the police.
Rallies are also planned in Moscow later on Sunday, part of a campaign to win the release of President Vladimir Putin's most prominent opponent. He was arrested on January 17 after returning from Germany where he had been recovering from a nerve agent poisoning in Russia last summer.
Police have said the protests have not been authorised and will be broken up as they were last weekend. OVD-Info, a protest monitoring group, said that more than 4,000 people were detained at the rallies last week.
In the far eastern city of Vladivostok, where a rally began at 0200 GMT, police prevented protesters from accessing the centre, forcing them to relocate to the waterfront and the frozen waters of the Amur Bay.
Video footage showed protesters chanting "Putin is a thief" as they linked hands and marched on the ice in temperatures of around -13 degrees Celsius (8.6 degrees Fahrenheit).
In Tomsk, the Siberian city that Navalny visited before suddenly collapsing on a domestic flight last August, demonstrators gathered in front of a concert hall and chanted "Let him go!" and held up Russian flags.
OVD-Info said police had detained 145 people, including 76 in Vladivostok, since the rallies began.
Navalny's supporters in Moscow plan to gather at 0900 GMT near the Kremlin administration and the headquarters of the FSB, the KGB's successor, where protesters in 1991 famously pulled down a statue of the secret police's founder during the Soviet breakup.
Authorities have closed seven metro stations in the Russian capital and have said they will restrict pedestrian movement in the area due to the protest plans. There was a heavy police presence in central Moscow early on Sunday.
Navalny, a 44-year-old opposition politician, accuses Putin of ordering his murder, which the Kremlin denies.
He is accused of parole violations which he says are trumped up. A court is due to meet next week to consider handing him a jail term of up to three and a half years.
The protests following Navalny's dramatic return to Moscow despite the threat of arrest put Putin in a quandary over how to respond. Polls show pent-up frustrations among Russians over years of falling wages and fallout from the pandemic.
The West has told Moscow to let Navalny go and his allies have appealed to U.S. President Joe Biden to sanction 35 people who they say are Putin's close allies.
To galvanise support at home in an online video viewed over 100 million times, Navalny has accused Putin of being the ultimate owner of a sumptuous Black Sea palace, something the Kremlin leader has denied.
On the eve of the protests, Arkady Rotenberg, a businessman and Putin's former judo sparring partner, said he owns the property.
Many of Navalny's prominent allies were targeted in a crackdown this week. Several, including his brother Oleg, are under house arrest.