Russia detains more than 5,000 at protests backing jailed Kremlin critic Navalny

Riot police broke up protests across Russia on Sunday in support of Kremlin critic Alexei Navalny, detaining more than 5,000 people who had braved the threat of prosecution to demand he be set free.

In a massive show of force, police imposed a sweeping security lockdown in the heart of Moscow, sealing off streets to pedestrians near the Kremlin, closing metro stations and deploying hundreds of riot police as snow fell.

At one point, a column of protesters marched towards the prison in northern Moscow where Navalny is being held, chanting "Let him go!". In another scene, people in a crowd raised their hands above their heads in front of a row of riot police and chanted "we're not your enemies".

Navalny was arrested on January 17 after returning to Moscow from Germany where he had been recovering from a nerve agent poisoning in Russia last summer. He accuses President Vladimir Putin of ordering his murder, which the Kremlin denies.

His dramatic return to Moscow despite the obvious threat of arrest and the second straight weekend of protests at his jailing pose a challenge for Putin who has dominated the Russian political landscape for more than two decades.

Police said protesters could face criminal prosecution for attending or calling for an unauthorised demonstration and warned they could spread COVID-19.

Navalny's allies used social media to repeatedly change the location of their rally, scattering the crowds over different parts of Moscow and making it harder to disperse.

Police put turnout at Sunday's Moscow protest at around 2,000 people. Reuters reporters estimated crowds of several thousand, smaller than last weekend.

In St Petersburg and Moscow police used force to detain protesters and were occasionally seen using tasers. One protester had a bloodied, bandaged head.

At least 5,021 people were detained nationwide, including 1,608 in Moscow, according to OVD-Info, a protest monitoring group.

Yulia Navalnaya, the Kremlin critic's wife, was among those detained. She was later released.

"If we stay quiet, then they could come for any of us tomorrow," she wrote on Instagram before joining the protests.

The protest is a test of Navalny's support after many of his prominent allies were targeted in a crackdown this week. Several, including his brother Oleg, are under house arrest.