Vladmir Putin's main rival, Navalny was arrested at an anti-corruption rally in Moscow
Navalny was hurled into the back of a police truck after organising a rally calling for the resignation of Russia’s prime minister Dmitry Medvedev over corruption allegations.
Protesters trying to free Navalny reportedly surrounded the truck and blocked it from leaving for several minutes.
At least 500 other protestors have been detained in the capital and across the country by Russian forces.
Images show former Russian MP shot dead in Kiev Thu, March 23, 2017
Denis Voronenkov was killed in the Ukrainian capital of Kiev
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Ukrainian police experts look for evidence next to the body of former Russian MP Denis Voronenkov after he was shot dead on March 23, 2017 in the center of Kiev
The protests are the largest anti-government demonstrations since the 2011-12 demonstrations following a fraud-tainted parliamentary election.
Nalvalny later tweeted: “Guys, I’m fine. No need to fight to get me out… Our topic of the day is the fight against corruption.”
The activists claimed police stormed the office of his foundation and detained its staff as the broadcasted the protests.
The fierce Putin-critic called for the nationwide protests after he published reports claiming Medvedev controlled mansions, yachts and vineyards – a fortune that far outstripped his official salary.
But Mr Medvedev's spokeswoman blasted the allegations as "propagandistic attacks”.
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Protestors tried to free Alexei Navalny from the clutches of the police
More than 500 other protestors across Russia were also detained during the huge protests
The protests were launched after Navalny declared himself a candidate in Russia's next presidential elections in next March 2018.
Putin is expected to stand and win another six-year term, and sources close to the presidential administration say that after some discussion, a decision has already been taken not to allow Navalny to take part.