Russian authorities arrested Alexei Navalny, President Vladimir Putin’s fiercest critic, along with hundreds of other protesters who took to the streets following the arrest of a journalist.

The mass arrests on Wednesday came after thousands of people participated in an unauthorized rally in support of freedom of the press and investigative journalist Ivan Golunov who was arrested on drug charged but later released after the government admitted there was no evidence he committed a crime.

RUSSIAN NEWSPAPERS PUT UP RARE, UNITED FRONT FOLLOWING JOURNALIST'S ARREST

“We should not stand down, even if Ivan is free. There are a number of other people in his situation in this country,” said Maxim Reznik, a member of the St. Petersburg City Council who attended a smaller demonstration in that city.

Putin dismissed on Thursday two senior police officers involved in the arrest of Golunov. The Kremlin announced the firing of Moscow police's anti-drugs chief, Yuri Devyatkin, and head of the police department for western Moscow, Andrei Puchkov.

Police said over 200 people were arrested during the Moscow demonstration, though independent groups say the figure was more than 400.

The Interior Ministry said those arrested are facing charges that could bring up to 20 days in jail, according to state news agency Tass.

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For Navalny, the 42-year-old arch nemesis of Putin and leading opposition leader, the possible jail sentence is a daily reality. He has already served numerous jail sentences for spearheading a series of unsanctioned protests across Russia.

The protester said the June 6 arrest of Golunov on bogus charges of dealing synthetic stimulants was a set-up as retaliation for his reporting on Moscow City Hall and the city’s crime-ridden funeral industry.

Police initially circulated photos of drugs allegedly taken in the journalist’s apartment, but later confessed that the images came from another case. Defense lawyers, meanwhile, said Golunov’s fingerprints weren’t on any of the drug packets allegedly found in his apartment.

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The injustice prompted media organizations to condemn the arrest, with three of Russia’s most respected newspapers published near-identical front pages Monday reading “I/we am/are Ivan Golunov.”

The Associated Press contributed to this report.