MOSCOW (Reuters) - Several hundred protesters gathered in Moscow on Sunday in a small, government-authorized rally supporting investigative journalist Ivan Golunov and decrying abuse of power over his five-day arrest this month on drug charges.

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The 36-year-old reporter, known for exposing corruption among Moscow officials, was freed following an outcry by supporters who said he was framed by corrupt police.

Journalists critical of Russian authorities have led a dangerous existence since the 1990s - sometimes threatened, attacked or even murdered over their work - but Golunov’s case triggered an unusually strong backlash.

An unsanctioned rally on June 12, the day after he was released, led to more than 500 detentions, including opposition politician Alexei Navalny.

But Sunday’s event was given the go-ahead, raising questions over whether President Vladimir Putin’s government was trying to provide a safety valve for public anger.

The rally, called by the Russian Union of Journalists and named “Justice and Fairness to Everyone”, had drawn a few hundred people by early afternoon, a Reuters witness said. State news agency TASS cited police saying around 1,600 were there.

Computer programmer Sergey, 28, said he was attending in the hope the protest would help stop others having drugs planted on them as he believes happened to Golunov. “Someone has to (protest),” he said, noting the small number at the rally.

Other demonstrators drew attention to detentions of regional journalists. “Moscow, Golunov is free. What about the others?” one of the banners read.

Putin fired two police generals over the case on Thursday, and other officers involved have been suspended pending an investigation.

Golunov was invited to Sunday’s event but did not turn up.