In pictures: Tens of thousands gather for pro-Navalny protests

A protester holds a poster that reads "One for all and all for one" in support of opposition leader Navalany

Tens of thousands of people rallied across Russia on Saturday in some of the largest demonstrations held against President Vladimir Putin in years.

Crowds defied police to show support for opposition leader Alexei Navalny - who was arrested last weekend after returning to the country following a near-fatal nerve agent attack last year.

Monitors say more than 3,000 were arrested for taking part in rallies in dozens of cities across the country.

Reuters estimated that some 40,000 gathered in Moscow alone, but authorities played down the figure and said only a tenth of that number showed up.

Riot police were pictured dragging away and beating some protesters. The US and UK have condemned the heavy-handed response and called for the release of peaceful protesters.

Josep Borrell, the EU foreign policy chief, also expressed concern and said foreign ministers would discuss "next steps" on Monday.

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OVD Info, an independent NGO that monitors rallies, said more than 1,200 had been detained in Moscow alone.

Demonstrations, held from Russia's Far East to St Petersburg, were some of the biggest seen in years.

In Omsk protesters braced freezing temperatures of almost -30C (-22F) to protest against Mr Navalny's detention.

And conditions were even colder, -52C (-62F), at another protest held in Yakutsk in Siberia.

Mr Navalny, a lawyer and blogger, has long been a thorn in the side of the Kremlin. He forged reputation as an anti-corruption campaigner and has become the most prominent face of the country's opposition.

He was arrested immediately on arrival into the country last Sunday after flying home from Germany, where he had been recovering from an attempted assassination attempt which he and investigative journalists have blamed on Russian authorities - a claim officials deny.

Police said Mr Navalny had violated parole conditions and have kept him in custody pending further hearings.

Much of the international community have condemned his arrest and called for his immediate release.

Mr Navalny called for street protests and his team further galvanised support this week after releasing an investigative documentary about an opulent Black Sea property allegedly owned by President Putin.

The investigation, now watched more than 70m times, alleges the property cost £1bn ($1.37bn) and was paid for "with the largest bribe in history" but the Kremlin denies it belongs to the president.

Russian authorities had warned in advance of Saturday that any unauthorised demonstrations would be "immediately suppressed".

Some demonstrators were pictured with injuries, including wounds to the head, following the promised crackdown.

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