More than 5,000 people have been detained at demonstrations across Russia in support of opposition leader Alexei Navalny, rights activists said on Sunday.
The number of people taken into custody during this second weekend of mass pro-Navalny protests was about 1,000 higher than a week ago, an indication of both the resolve of demonstrators and the determination of Russian authorities to crack down on them.
Over 1,500 people were detained on Sunday in Moscow alone, according to OVD-Info portal, which monitors law enforcement in Russia.
In Saint Petersburg, the second-biggest city in Russia and President Vladimir Putin's home town, the tally stood at over 860 people. More than 50 other cities saw protesters apprehended, said the monitor.
Human rights activists condemned the heavy-handed police tactics against the demonstrators, including the use of stun guns, tear gas and physical violence.
In Kazan, about 700 kilometres east of Moscow, detained students reportedly had to take off their underwear and hand over cell phones and their belongings. Images from the city of Kazan also showed several demonstrators forced to lie down in the snow by police.
Navalny's wife, Yulia, was among those detained in the capital, after posting a picture on Instagram of herself on the street.
She was released on Sunday night after being held for several hours.
According to media reports, she is to go on trial on Monday for taking part in the unauthorized action and faces a prison sentence of several days.
Earlier in the day she had railed against the house arrest imposed on her husband's brother, Oleg Navalny, referring to him as a "hostage."
Yulia Navalnaya was also held a week ago at similar mass protests in Moscow.
Near FSB headquarters
Police in riot gear in the capital used fencing to block protesters from reaching a planned meeting place near the headquarters of the FSB security agency, according to a reporter at the scene.
The police action led organizers to point supporters to new meeting points. A procession of thousands moved to the Moscow remand prison where Navalny is being held, shouting "Let him go." According to the dissident leader's team, Navalny could hear the shouting in his cell.
Police had warned that Sunday's rallies were unauthorized and that participants would face legal consequences. In an effort to dampen the protests in Moscow, authorities had closed seven metro stations, and shops, cafes and restaurants will not be allowed to open.
US Secretary of State Antony Blinken criticized Russian authorities for their heavy-handed treatment of anti-government protesters.
"The US condemns the persistent use of harsh tactics against peaceful protesters and journalists by Russian authorities for a second week straight," tweeted Blinken, who has been in the post for less than a week as part of President Joe Biden's new administration.
The Russian Foreign Ministry fired back, accusing the US of "gross interference" in its domestic affairs.
Bulgaria, Czech Republic
The Bulgarian and Czech foreign ministries also condemned the harsh measures taken against protesters.
Czech Foreign Minister Tomas Petricek said that his country would plead within the European Union to impose sanctions on certain responsible parties, according to the CTK agency.
Czech President Milos Zeman, on the other hand, said in a radio interview that from his point of view, Navalny was a Russian nationalist who was primarily against Russian President Vladimir Putin because he wanted to take his place.
Last weekend, hundreds of thousands of people took to the streets to call for Navalny's immediate release and to protest against Putin.
Rights activists estimate that 4,000 people were arrested and many were injured at the unprecedented protests.
They also took aim at Navalny's associates in recent days, with his brother Oleg, his associate Lyubov Sobol and other supporters being sentenced to two months of house arrest.
Navalny returned to Russia earlier this month after receiving treatment in Germany following a near-fatal assassination attempt with the nerve agent Novichok. He was immediately detained upon his arrival in Moscow and sentenced to pretrial detention.
A Russian court on Thursday confirmed his 30-day pretrial sentence, rejecting an appeal by the dissident's lawyers to set him free.
At a trial scheduled for Tuesday, a court is to decide whether his earlier sentence will be commuted into real imprisonment. Navalny's team announced new protests if he is sentenced to prison on Tuesday.