At least 5,300 people were arrested in 88 cities, especially in Moscow (1,800) and St. Petersburg (1,176), according to the organisation OVD-Info, which specialises in monitoring demonstrations. They point out that this is a record number in the history of modern Russia. According to the Union of Russian Journalists, at least 60 members of the press have been arrested.
Supporters of Alexei Navalny demonstrated on Sunday 31 January during a day of mobilisation to demand the release of the imprisoned opposition figure. Growing tension was experienced with the Russian authorities and the police who deployed a large number of police officers. In addition, access to the centre of several cities has been closed to prevent unauthorised gatherings of protesters.
The protesters originally intended to gather in front of the headquarters of the Federal Security Service (FSB), the groups went to the detention centre where Navalny is being held, but were unsuccessful and returned to the centre of Moscow.
In the early afternoon, Navalny's team announced the end of the demonstration in Moscow. Alexei Navalny's wife, Yulia Navalnaia, was detained by police on her way to the rally, according to opposition media reports.
Meanwhile in St. Petersburg, almost 2,000 people gathered in a central square but were dispersed by riot police and police made several arrests.
In Novosibirsk, Russia's third largest city, independent media "Taiga" estimated the number of protesters at more than 5,000, one of the largest anti-government demonstrations in recent years.
Most of Navalny's close allies were placed under house arrest on Friday 29 January by Russian courts, two days after a series of searches that mainly targeted his wife's home and the premises of his organisation, the Anti-Corruption Fund.
US Secretary of State Antony Blinken denounced on Twitter Russia's continued use of brutal tactics against peaceful protesters and journalists for the second week in a row. He also called on the Russian authorities to release Navalny and his supporters.
"What we are seeing today has nothing to do with protecting rights or fighting for a better life. What we are seeing today is a provocation," Vladimir Putin's human rights envoy Valeri Fadeev responded. "Enormous US interference in Russia's internal affairs is a fact, such as the promotion of false information and calls to participate in illegal actions by Washington-controlled internet platforms," Foreign Minister Sergei Lavrov said on Facebook.
EU Chancellor Josep Borrell on Twitter deplored the mass arrests and the disproportionate use of force.
Navalny returned to Russia on 17 January after months recovering in Germany from a poisoning he accuses President Vladimir Putin of. He called on Russians to take to the streets via his blog. Last Saturday saw the first gatherings of dozens of Russians across the country resulting in more than 4,000 arrests and the opening of 20 criminal cases.
They take place in the context of Navalny's appearance before judges, scheduled for next week. Since his return to Russia, the opponent has been the subject of a multitude of politically motivated legal proceedings. The opponent faces around two and a half years in prison for violating the terms of a three-and-a-half-year suspended prison sentence imposed on him in 2014.
Authorities had earlier warned Navalny's supporters that protesters could be prosecuted for "mass riots" if the rallies end in violence. Roskomnadzor, Russia's telecommunications gendarme, announced that it was sanctioning social networks for "leaving messages encouraging minors to demonstrate".
The protests have also been sparked by the release of an opponent's investigation accusing Putin of benefiting from a huge palace valued at more than a billion euros on the shores of the Black Sea. The president has denied the accusations and links them to Russian brainwashing. Public television has broadcast images showing the construction of the residence, but far from the luxury described by the opponent.